The Scientific Rationale
Behind The Ideal Weight
Program
A Dan’s Plan E-Book
1. Introduction ………………………………………………………………………………………….
3
2. How food intake and body fat stores are regulated ……………………………
5
3. Energy regulation ………………………………………………………………………………….
5
4. Energy homeostasis system …………………………………………………………………
6
5. Appetite regulation ……………………………………………………………………………….
9
6. The reward of food………………………………………………………………………………..
10
7. The modern world: A changed environment ………………………………………
14
8. Food supply and food culture have changed ………………………………………
14
9. Convenience ………………………………………………………………………………………….
17
10. Eating Culture ……………………………………………………………………………………….
18
11. How Our Surroundings Influence Food Intake …………………………………….
18
12. Strategies for losing body fat ……………………………………………………………….
21
13. Leverage satiety ……………………………………………………………………………………
21
14. Control the food environment ………………………………………………………………
23
15. Modify the body fat setpoint ………………………………………………………………..
24
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 1 16. Support Digestive Health ………………………………………………………………………
27
17. Ideal Weight and Sleep ………………………………………………………………………..
30
18. How much sleep are we getting? ..................................................................
31
19. Why are we getting less sleep? …………………………………………………………….
31
20. Potential Causes of Weight Gain due to Insufficient Sleep ………………….
32
21. Sleep and Inflammation ……………………………………………………………………….
33
22. Circadian Rhythms & Body Weight ………………………………………………………
34
23. Insufficient Sleep, Food Intake, and Fat Loss ………………………………………
35
24. Cognition, sleep, and weight gain ………………………………………………………..
36
25. Executive Functions ………………………………………………………………………………
36
26. Sleep Loss and Increased Pleasure Eating …………………………………………..
38
27. Sleep Conclusion ……………………………………………………………………………………
39
28. Ideal Weight and Physical Activity ……………………………………………………….
40
29. Stand and Walk …………………………………………………………………………………….
41
30. Walking ………………………………………………………………………………………………….
44
31. Exercise ………………………………………………………………………………………………….
45
32. Exercise and Weight Control …………………………………………………………………
47
33. Closing …………………………………………………………………………………………………..
48
34. References …………………………………………………………………………………………….
49
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 2 Introduction
Statistically speaking, in the United States it is no longer ‘normal’ to be lean: two-thirds
of US adults are obese or overweight [1], and other industrialized nations are following
closely behind.
Judging by the diet books lining virtual bookshelves, the gym
memberships, and the nearly infinite variety of weight loss supplements, people are
looking for a solution. Judging by the results and continuing trends, currently available
solutions are not solving the problem for most people.
Anyone who has tried to lose fat knows it’s a challenge. Body fat isn’t easy to lose, and
it’s even more challenging to maintain a reduced body fat level over a long period of
time. This relates to key problems that must be addressed by an effective fat loss
program. Many programs don’t sufficiently redirect people from the diet and lifestyle
factors that cause fat gain to begin with. In addition, fat loss itself activates the body’s
‘starvation response’ in many people, resulting in increased hunger, increased
preoccupation with food, decreased energy for physical activity, and a slow
metabolism. Despite the dieter’s best efforts, eventually the body wins the struggle
and the fat is regained. Research has shown that the solutions that were initially
proposed for fat loss, such as simply eating less of the usual diet, exercising, or eating a
low-fat diet, are not very effective stand-alone strategies for most people. If a fat loss
strategy is only marginally effective, it may not justify the effort required to implement
it. The good news is that since then, research has uncovered strategies that are
effective, and these form the basis of the Ideal Weight Program.
To meet the challenge of reducing body fat and sustaining leanness, we need a
program that targets the key factors that determine body fatness.
This involves
redirecting the diet and lifestyle in a manner that naturally promotes leanness and
health, working with the body rather than against it. We also need a program that’s
accessible, engaging, practical, and mostly importantly, healthy. The knowledge gained
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 3 from cutting-edge scientific research-- on food intake, body fat regulation, and the
behavioral sciences-- has made this possible, but much of this information has not yet
trickled down into popular weight loss programs. That’s why we brought together a
team of scientists to design the Ideal Weight Program.
The prevalence of obesity has increased dramatically over the last century, and
particularly over the last 30 years, yet we didn’t experience a sudden dramatic shift in
our genetic makeup over this period [1]. Our genes have remained the same, but the
world in which we live has changed radically, placing the human body outside its
normal operating parameters. We argue that the ‘normal’ modern lifestyle, very unlike
that of our ancestors, is an unnatural condition for the systems in the body that
unconsciously determine body fatness, and that this promotes fat accumulation. For
most people, this means that living a typical lifestyle in our modern world leads to a
predictable increase in body fatness across life.
The purpose of this document is to help you understand the key elements of diet and
lifestyle that matter in weight regulation. The other Ideal Weight Program materials
describe how to apply this knowledge to achieve and maintain your ideal weight.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 4 How food intake and
body
fat
stores
are
regulated
Energy Regulation
Fat tissue is the main energy (calorie) storage site of the body—think of it like a bank
account. When you eat less energy than your body uses, your body withdraws from
the account to allow enough energy to keep itself running properly. When you eat
more energy than your body needs, the excess energy is deposited in fat tissue. As far
as we currently know, the type of energy consumed - carbohydrate, fat or protein doesn’t have a major influence on whether it will be deposited in fat tissue or not [2, 3],
although it does influence how much a person eats—an important point we’ll come
back to later.
Eating fewer calories than the body burns causes fat loss, and eating more calories
than the body burns causes fat gain.
Since one pound of body fat represents
approximately 3,500 calories (technically, kilocalories), it is tempting to think that
increasing food intake by 100 calories per day should lead to one pound of fat gain
over 35 days, approximately 10 pounds over a year, and 50 pounds over five years.
However, this is not correct for two reasons. First, a larger body requires more energy
to maintain, and so as a person gains mass, the energy requirement increases until it
cancels out the extra 100 calories, equilibrium is reached, and fat gain ceases [4].
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 5 Second, the body has the ability to speed up or slow down the rate at which calories
are burned, partially compensating for excesses and shortfalls [5, 6]. Some people are
better at doing this than others, and people who are not able to burn off extra calories
are more susceptible to fat gain over time [6].
For a similar reason, if you eat 100 fewer calories per day than your current calorie
usage, you will not lose 10 pounds of fat over one year, 50 pounds over five years, etc.,
as simple arithmetic would predict [4]. This is because a smaller body needs less fuel.
As we lose tissue during weight loss (including some lean mass), the amount of energy
required for daily functioning also diminishes. Additionally, the body slows down the
rate of calorie expenditure in an attempt to prevent further fat loss [5]. The degree to
which metabolism slows during weight loss depends on the individual, and is probably
a major determinant of fat loss success.
The amount of food a person eats varies greatly from day to day. On a single day,
there isn’t a very tight correspondence between calorie intake and the body’s calorie
needs (for weight maintenance) [7]. However, over longer time periods, calorie intake
and calorie needs typically correspond closely to one another [7]. How does the body
maintain this careful long-term balance between energy withdrawals and deposits?
And why does the body resist losing fat, even when it is clearly present in excess? The
answers lie in the energy homeostasis system.
Energy Homeostasis System
We have to eat to survive, and we have to be well-nourished to reproduce. Therefore, it
makes sense that we have a highly-tuned system to regulate feeding and energy
stores. The brain is at the center of this system, and it receives signals from the gut
about the quantity and composition of the food you eat, signals from your sense
organs about the sensory qualities of your meals, and signals from fat tissue about the
quantity of stored fat [8]. In the brain, a region called the hypothalamus serves as the
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 6 primary control center of the system that regulates body fatness [9]. It acts in a
manner similar to the thermostat in your home. If you set your thermostat to a certain
temperature, say 72° F, the thermostat uses a thermometer to sense if the ambient
temperature begins to deviate from this temperature ‘setpoint’. If the temperature of
your home increases, the thermostat applies air conditioning to bring the temperature
back down to 72 ° F. If the temperature decreases, the thermostat applies heat to
bring the temperature back up. This process of dynamic self-regulation in order to
maintain stability is called ‘homeostasis’, and it is fundamental to many processes in
the body such as the regulation of temperature, blood pressure, and body fatness. The
system in the body that regulates body fatness is called the ‘energy homeostasis
system’, and it will be a major focus of this document.
A thermostat uses a thermometer to detect changes in temperature, but what signal
does the brain use to detect body fatness? Researchers have suspected since the
1950s that a hormone informs the brain of fat tissue size [10]. However, it wasn’t until
1994 that researchers identified the hormone—leptin [11]. Fat tissue produces leptin
in proportion to the amount of stored fat, and this leptin travels through the
bloodstream to the brain, informing the brain of how much fat is currently stored in the
body [9]. When fat tissue shrinks during weight loss, circulating leptin declines, and the
brain detects the decline in circulating leptin. When fat tissue grows during weight
gain, circulating leptin increases, and the brain also detects this increase [8]. There are
other signals besides leptin
that also inform the brain of
energy status (insulin, ghrelin,
amylin, and perhaps others),
but leptin is the dominant
player and it is sufficient to
illustrate the principle. The
essential point is that fat
tissue is not simply a passive
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 Figure 1 Normal Weight Fluctuation (Dan's Plan Weight Chart) 7 storage site for energy, it is a hormonally active tissue that communicates with the
brain.
Under certain conditions, a ‘setpoint’ in the body can be adjusted up or down. This
would be equivalent to turning your thermostat up to 80° F. Now the thermostat is
‘defending’ against deviations from 80° F instead of 72° F. The natural trajectory of
non-industrial cultures, as well as US citizens 120 years ago, is to maintain relative
leanness throughout life [12-14]. The modern trajectory is to gain weight in each
decade of life until old age. This is because some combination of factors in our modern
environment promotes fat gain to a degree that exceeds our body’s natural ability to
defend against it. An additional problem is that as fat mass increases gradually over
time, the energy homeostasis system actually ‘defends’ the progressively higher fat
mass against changes [8]. Rather than protecting against the gradual increase in body
fatness over time, the setpoint increases similar to the thermostat in your home, and
this makes fat loss difficult because the body no longer ‘wants’ to be lean.
The brain may be more effective at preventing fat loss than preventing fat gain. This
makes sense because our distant ancestors would have been more threatened by food
shortage than food excess, and far more threatened by starvation than overeating. In
today’s world, many people have the great fortune of food security. The threat of
starvation has disappeared for most, replaced by the new threat of persistent
abundance —a threat to which our ancient bodies are poorly adapted. If our bodies
are less effective at defending against fat gain than fat loss, this implies that small
increases in body fatness can accumulate and perhaps eventually be ‘defended’
against changes. This has been observed on a population level during the holiday
season in the US. For many, body weight increases during the 6-week period between
Thanksgiving and the New Year, a portion of it is lost in January, but most of it remains
to be expanded the following year [15]. This suggests that to some extent, the higher
body weight acquired during holiday feasting has become the new setpoint.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 8 Appetite Regulation
While the energy homeostasis system regulates body fatness, another system called
the ‘satiety system’ regulates appetite on a meal-by-meal basis [8, 16]. ‘Satiety’ is
another word for the sensation of fullness, which suppresses the desire to eat. As you
eat a meal, the digestive tract sends signals to the brain that indicate the quantity and
type of food you have consumed [16]. The brain receives these signals and gradually
makes you feel full (satiated), temporarily shutting down your desire to eat. The
satiety system attempts to ensure that you eat an appropriate quantity of food at each
meal—not too little, and not too much.
However, satiety is only partially dependent on calorie intake. Some foods are more
filling than others, even if you consume an equal number of calories from each. This is
a fact that we will use to our advantage in this program. A number of food properties
influence the amount of satiety you experience per unit calorie. One is calorie density:
the more calories a food contains per unit weight or volume, the less satiating it is per
calorie [17]. In practice, calorie density is mostly determined by the water content of a
food. A dry cracker is denser than grain porridge, and this explains why grain porridge
is much more satiating per calorie than crackers. The palatability of a food (how good it
tastes) is also important; the more palatable a food, the less satiating it is [17, 18]. This
is why it is easy to overeat highly palatable foods such as ice cream, pizza and cookies.
If calorie density and palatability are held constant, fat and carbohydrate are equally
satiating, however, added fats increase calorie density and palatability and therefore
tend to provide very little added satiety value relative to the calories they provide.
Protein remains the most satiating nutrient of all, and it is a particularly useful fat loss
tool [17]. Fiber also contributes to satiety, and is also useful because it has very little
calorie value [17].
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 9 Not surprisingly, the satiety system functions optimally when one eats unrefined,
natural foods. Refined, calorie-dense, hyperpalatable modern foods don’t trigger
fullness to the same degree as unrefined whole foods, leading to an increase in calorie
intake that is often not perceived.
While your energy homeostasis system and satiety system collectively determine
appetite, they are not the only things that control food intake. If they were, eating
would be as exciting as putting gas in the gas tank: something you have to do to keep
moving, but you won’t find photos of it on Facebook. However, we know both from
common sense and scientific research that food intake is influenced by many factors
besides appetite. One of these is the seductiveness and pleasure associated with food
intake – ‘pleasure eating’ is one of several key factors that encourage fat accumulation
in the modern world.
The Reward of Food
Eating brings us pleasure, and this pleasure is a wonderful aspect of life. Food is often
at the center of meaningful life events such as holidays and weddings. We use food to
express love for others, and to reward ourselves. But, because pleasure can drive food
intake, it can also cause us to eat in the absence of hunger. We have all experienced
the sensation of being full after a meal, only to have a waiter offer a decadent dessert.
Suddenly we’re happy to eat several hundred additional calories that the body didn’t
need. Would a large bowl of plain oatmeal, containing the same number of calories,
have elicited the same response? Why not?
For our current purposes, the difference between chocolate cake (if you love chocolate
cake) and oatmeal (if you like oatmeal) involves two related properties called
palatability and food reward. Palatability is the pleasure associated with eating a food.
Chocolate cake simply tastes better than oatmeal. Some of this is related to the sugar,
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 10 the fat, and the calorie density of chocolate cake—properties that the pleasure centers
in our brain inherently recognize as valuable.
Food reward is the second key difference. The reward value of a food is its ability to
motivate behavior, in this case behaviors related to the acquisition and consumption of
the food in question. The reward system serves to guide us toward foods (and other
things) that would have been important for the survival and reproduction of our
ancestors. When food was difficult to find, and required effort to obtain and prepare,
eating a dense, fatty, sweet food would have been a very good idea. In today’s world,
awash in this type of food, it is no longer adaptive.
You can think of reward as the ‘seductiveness’ of food. The more rewarding a food, the
more likely you are to go out of your way to obtain it, and the more likely you are to
seek it out and eat it even if you aren’t hungry. Also, the more rewarding a food’s
properties (e.g. fat, sugar, salt), the more likely you are to acquire a taste for it and
begin to find it increasingly palatable over time [19, 20]. This is how we acquire a taste
for things like coffee or beer. Many people despise the taste of these bitter beverages
when they first try them. However, if a person continues to drink these beverages, and
the rewarding properties of caffeine and alcohol repeatedly stimulate reward centers
in the brain, eventually a preference for the taste emerges. Indeed, people love coffee
and beer, and it is not because we have an evolved taste for bitterness. It is because
the rewarding properties of these drugs motivate repeat consumption.
The reward system recognizes certain food properties that it considers ‘valuable’
because they would presumably have enhanced survival among our distant ancestors
[8]:

Calorie density

Sugar

Fat

Starch

Salt
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 11 
Free glutamate (meatiness or ‘umami’)

Absence of bitterness
The pleasure/reward experience is also influenced by things such food texture, crunch,
and mouth feel of food. Today, we have an unprecedented degree of control over our
food, and most of the food we eat is highly rewarding and calorie-dense by historical
standards. Much of this is due to commercially prepared food, including restaurants,
but one can also produce highly rewarding food in the home kitchen (e.g., brownies).
Food manufacturers use the properties listed above to design foods that are highly
rewarding and therefore reinforce repeat purchase behavior [21]. The larger the reward
response, the more likely you are to repeat that experience (e.g., purchasing salt and
vinegar kettle chips); or, the more powerful the craving will be to do so [22]. The good
news is that we can gradually ‘extinguish’ our craving for a food by avoiding it for long
periods of time. Salt and vinegar kettle chips have less power over you if you haven’t
eaten them in 6 months.
Reward, memory, emotional, and energy homeostasis centers are linked into a
functional unit in the brain. This means that these individual centers work together to
produce complex behaviors around eating. Rewarding food (think of anything you
crave) is in part perceived by an area of the brain called the orbitofrontal cortex [23].
The posterior part of this regions integrates all sensory input from a meal including
sight, smell, taste, etc. The anterior part stores the memory of how much you enjoyed
that particular meal. Once the memory of a meal is stored, it can influence future
behavior. This reflects a process called ‘reinforcement’: the rewarding experience
formed a strong positive memory, which then triggers you to repeat that same action
in the future. Think about the experience of being hungry and trying to decide where
you want to eat. It is during these times – and other more subconscious moments of
deciding what to eat – that these pleasure/reward memories trigger action. Just
thinking about a prior pleasurable experience can increase motivation and action to
attain this pleasure again.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 12 Many people find that eating ice cream three nights in a row makes them crave it
strongly on the fourth night, another example of reinforcement. This is why there have
been recent comparisons between highly rewarding food and drugs of abuse such as
cocaine [24]. The reward centers activated by these different substances overlap, and
so do the behaviors of animals (and humans) under their influence, respectively [24].
Some foods, such as ice cream, chocolate, and French fries, are so hyper-palatable and
hyper-rewarding that people can literally become addicted to them. Addiction is a
pathological over-activation of the reward system, causing excessive motivation for
the substance in question.
Animals under the influence of drugs or artificially
hyperpalatable food (a palatability level either unusual or unobtainable from natural
foods) will risk pain or even death to attain more of this pleasure [25, 26]. The ability of
these foods to modify our behavior is powerful. Even though most of us are not literally
addicted to food (no matter how much we weigh), highly rewarding foods can
nevertheless drive us to overconsume calories.
Over the last 50 years, our food environment has become increasingly dominated by
readily available, calorie-dense, highly rewarding, highly palatable foods– and this is
one of the main factors underlying the obesity epidemic [8].
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 13 The Modern World: A
Changed Environment
A bit more than a century ago in the United States, most people had never heard of a
calorie, and yet obesity was far less common than today [12].
To this day, in
numerous non-industrial populations throughout the world, obesity ranges from
uncommon to nonexistent even if food is plentiful [13, 14].
Why is maintaining
leanness so difficult today when it was effortless for our ancestors only a few
generations ago?
Food Supply and Food Culture Have Changed
The fundamental reason we’ve gained fat over the last three decades is that we have
experienced a growing imbalance between calorie expenditure and calorie intake on
an average day [27]. We are simply eating more than we used to, and pairing that with
an unprecedented amount of sedentary time. According to USDA data, Americans eat
approximately 350 more calories per day than we did in 1970 [28] (Figure 2). The best
available mathematical models suggest that the increase in calories consumed can
single-handedly account for the ‘obesity epidemic’ [27, 29]. Understanding this gets us
part of the way there, but the harder question that naturally follows is why do we eat
more today than we did in 1970? We didn’t collectively wake up one morning and
decide to eat an extra 350 calories—it’s the result of a profoundly altered food
landscape, including food culture, food composition, food availability, and food
advertising, as well as other factors that influence calorie balance such as physical
activity and sleep.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 14 Figure 2. Prevalence of obesity (NHANES) and calorie intake (USDA) between 1961 and 2009 in the US. Without stepping into a time machine, it’s difficult to fathom just how profoundly the
modern food environment has changed over the last century.
New methods of
processing whole foods have enabled previously unknown food products to become
common ingredients in our food supply. Indeed, over the last two centuries we have
increasingly distanced ourselves from eating food in its natural form. Commercially
prepared food is often created from nutritionally bankrupt ingredients that promote
overconsumption, including refined flours, added oils, sugar, and flavorings [21]. We’ve
increasingly
outsourced
food
preparation
from
our
own
kitchens
to
food
manufacturers and restaurants (Figure 3), and as a result we eat more processed food
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 15 than ever.
Home-cooked food has become progressively less common, and the
proportion of food expenditures spent on fast food has tripled since 1970 [30] (Figure
3).
Over the same time period, refined sugar consumption has increased by 19
percent, mostly in the form of nutritionally barren sodas sweetened with high-fructose
corn syrup [28]. Consumption of fresh potatoes has declined by 30 percent, to be more
than replaced by increased consumption of processed potatoes such as potato chips
[28].
Figure 3. Proportion of food expenditures spent on food eaten at home, food eaten away from home, and fast food, 1889‐2009. Commercial food is professionally designed and tested to reinforce its own repeat
purchase and consumption. Food scientists and professional chefs know exactly how
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 16 to craft foods we find irresistible [21]. As described, these foods tap directly into the
brain systems that make us crave, seek, and eat food. These foods also generally do a
poor job of producing satiety. Simply having these foods readily available in the food
environment increases the likelihood that we will consume more calories than we
need.
Novelty and variety can also increase food intake under experimental conditions [18].
It is estimated that 17,000 new food products are introduced to the market each year.
Not only are we outsourcing food preparation more than ever before, but a staggering
array of new food products/ingredients are constantly introduced into our food
environment [31]. This is one reason why diet/health authorities frequently suggest
shopping only around the periphery of a grocery store, thereby focusing food choices
on simple natural foods and avoiding aisles where a large variety of temping processed
foods are shelved.
Convenience
The convenience or ease of access to food is one of the strongest influences on
consumption [32]—to the extent that convenience itself can often explain which foods
people prefer, and how much they consume [33]. For example, whether or not a lid is
present on a jar influences how much people eat what’s inside the jar; if a can of cola is
within arm’s reach, a person is much more likely to drink it than if it were across the
table [34, 35]. Processed food is often ready to eat, minimizing the effort required to
consume it and allowing consumption at any time of day or night. The effort required
to prepare food from single ingredients is greater than the effort required to prepare
packaged food options, naturally limiting consumption to mealtimes. Therefore, in
addition to the factors listed above, the convenience of packaged foods increases the
propensity for overconsumption.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 17 Eating Culture
Food is becoming increasingly available at all times of day.
In the US, we eat
significantly more snacks per day than we did in the 1970s [36]. Some have even
argued that lax eating norms explain the rise in weight, because there is no longer a
social stigma against eating between meals. Because it is currently acceptable to eat
outside of designated meal times, it’s also easier to eat in the absence of hunger.
How Our Surroundings Influence Food Intake
Our surroundings influence how much we eat to a surprising degree [37].
Environmental factors can distract us from internal signals of fullness, prompting us to
eat past satiety. These include factors like the eating atmosphere (i.e., noise, lighting,
décor), the effort required to obtain food, social interaction during the meal, and any
other external factor that captures the attention [38]. Aside from the immediate
surroundings, a person’s food consumption is also influenced by how food is served to
them, including factors like food package design, package and plate size, number of
options (tapas, anyone?), plate shape, cup shape, utensil size, etc. [31].
In 2005, Professor Brian Wansink published a now infamous study measuring calorie
consumption by people eating soup. This study had two conditions: one where subjects
ate from normal bowls and one where subjects ate, unknowingly, from bowls that
were secretly and undetectably refilled from the base of the bowl as the subjects ate
from them. This study yielded three very interesting findings: first, subjects ate 73%
more soup when eating from the self-refilling bowls; second, despite consuming three
quarters more calories, they did not believe they had consumed more, and third, they
did not perceive themselves to be more full than the group eating from normal bowls
[39]. This study illustrates the fact that the perception of fullness is based in part on
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 18 external factors, in addition to internal factors such as the detection of nutrients by the
digestive system. Together, a variety of environmental influences significantly affect-or disguise-- how much you eat, and together these factors play a key role in weight
control.
Distractions are particularly problematic in combination with large portions sizes,
because instead of eating until we recognize we’re satisfied, we often eat until our
plate is clean [40, 41]. There is a high risk of overeating in places like restaurants, when
eating with multiple people, and while eating in front of the television. In addition,
social and environmental factors can suggest alternative norms for how much you
should consume. Research has shown that the risk of overeating increases in parallel
with the number of people at the table [42-44]. This is not only due to distraction, but
also because the fact that the person who eats the most at the table subconsciously
establishes a norm for how much everyone else should eat [31]. If you eat with
someone who takes four sausage links from a community plate, you’re much more
likely to take two or three yourself, where otherwise you might have only taken one.
These factors can have a surprisingly large influence on how much we eat—the
remarkable potential to double your normal calorie intake at any given meal [45].
However, we often wrongly believe that we are unaffected by these factors [46]-- “this
happens to other people, but not to me.” And with food – like with any other habit – if
these overeating behaviors occur frequently enough, a new pattern of eating risks
becoming your default eating style. In other words, it is easy to develop the habit of
eating well past satiety, and when that habit is established, you consistently override
your body’s natural attempt to limit calorie intake.
Together our food environment, culture, and ancient biological drives encourage us to
eat beyond internal fullness cues, and as a result many of us gain fat, despite the
existence of an energy homeostasis system meant to oppose excess fat accumulation
[47]. Many of us can overwhelm our body’s defenses against fat gain, and it isn’t
particularly difficult when conditions favor it. Research over the last three decades has
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 19 shown convincingly that when people are placed in an environment with a variety of
easily accessible, energy-dense, highly palatable, refined foods, they will overeat
without realizing it and gain fat [48, 49]. That is the situation in which most of us find
ourselves today. We are now faced with a food environment (available products,
cultural norms, outsources meal production, etc.) in which simply going with the flow is
enough to cause us to accumulate fat. What can we do about it?
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 20 Strategies for losing
body fat
Losing fat requires a state of ‘negative energy balance’ in the body, meaning that
fewer calories are entering the body than are leaving.
What may seem
counterintuitive (except to those who have attempted it) is that simply eating less of
the same food, or exercising more, is not a very effective long-term fat loss strategy for
most people. Although it can work if adhered to stringently, controlled trials suggest
that it usually does not result in significant, durable fat loss [50]. The question is, how
do we make the body ‘want’ to shed fat, so we can naturally achieve and sustain
leanness?
Leverage Satiety
Satiety, or fullness, is one of the main factors that determines calorie intake, and it is
perhaps the simplest factor to control. As previously described, the degree of fullness a
person feels is only loosely determined by the number of calories consumed. It follows
that if we can provide the maximum amount of satiety with the minimum number of
calories, overall calorie intake will decline. Protein is the most satiating nutrient per
calorie [17]. We would expect that eating food with a high proportion of protein should
reduce overall calorie intake and body fatness, and this expectation has been
supported by numerous controlled trials [51-53]. Recent research has suggested that
increased protein consumption may be a key reason why low-carbohydrate diets tend
to be more effective for fat loss than low-fat diets (though neither low-fat nor low-
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 21 carbohydrate diets produce very impressive results as a stand-alone fat loss measure
in clinical trials) [52].
The calorie density of food also has a major impact on satiety. As we discussed earlier,
more calorie-dense foods provide less satiety per calorie [17]. Reducing the overall
calorie density of the diet lowers calorie intake and produces weight loss in diet trials
[54, 55]. A key determinant of calorie density is a food’s water content [17]. Foods
with a high water content, such as fruit, oatmeal, meats, and vegetables tend to be
more satiating per calorie than foods that are proportionally drier [17]. Another major
determinant of calorie density is a food’s fat content. Added fats can greatly increase
the calorie density of foods, resulting in a large increase in calorie intake due to a
decrease in the satiety produced per calorie [56]. That being said, a moderate amount
of fat can also paradoxically increase satiety because it delays the emptying of the
stomach. The best strategy for fat loss is to consume fats in the context of foods with
a naturally moderate or low calorie density, such as meats and avocados, but avoid
added fats except in small quantities. Very low-fat diets are generally perceived as
unsatisfying, and long-term adherence tends to be poor. Although there was a lot of
excitement about low-fat diets in the 1980s and 1990s, we now have a large amount
of evidence suggesting that this strategy is not very effective as a stand-alone fat loss
measure [57-59]. A good strategy is to eat a moderate quantity of fats as part of
unprocessed whole foods, but limit added fats.
Fiber is another factor in satiety. Refined carbohydrate contains very little fiber and
tends
to
produce
proportionally
less
satiety
than
unrefined
carbohydrate.
Consequently, whole grains, beans and fruit are more satiating than refined grains and
sugars, per calorie [17]. Although whole grain bread is more satiating than white
bread, bread tends to be a low-satiety food regardless of fiber content, because it is
calorie-dense. This may seem counterintuitive, but as soon as bread is chewed, the air
it contains escapes, and what remains has a high calorie density. Flour-based foods in
general are poor choices for fat loss, particularly if they include fat and/or sugar (e.g.,
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 22 pizza and pastries).
Eliminating flour-based foods during fat loss will significantly
improve results, and it will also enhance weight maintenance. Although nutrition
authorities frequently recommend whole grains as a part of a healthy diet, flours do
not provide any nutritional value that cannot be obtained from other foods. In other
words, flour-based foods are not an essential part of the diet. Many people find weight
control easier when they replace flour–based foods with other sources of unprocessed
carbohydrate such as sweet potatoes, potatoes, beans, oatmeal, and fruit.
As described earlier, high food palatability can encourage the consumption of food in
the absence of hunger, and beyond fullness. However, people don’t adhere to diets
they find unappealing. Fortunately, research suggests that simply avoiding foods with
the highest level of palatability delivers most of the benefit [60]. These tend to be
highly processed, calorie-dense foods that a dieter (or anyone else for that matter)
would want to avoid anyway. For sustainable weight control, you can eat satisfying
food that you enjoy, appreciating the natural flavors of quality ingredients.
Control the Food Environment
As described previously, the food environment has a major impact on the composition
and quantity of food consumed. In the modern fattening food environment, we are
surrounded by highly convenient, highly rewarding, highly palatable, calorie-dense
refined foods. We’re also bombarded by food cues in advertising that trigger hunger
and cravings. Most of us are susceptible to these factors, though we may not always
recognize it.
The three main keys to creating a healthy food environment are 1) do not allow easily
consumed food in your surroundings except at mealtime; 2) make poor choices
inconvenient and good choices convenient, and 3) to the extent possible, minimize
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 23 exposure to food cues. The goal is to reduce the need for willpower, a resource that
often fails, by investing a modest amount of effort in creating a food environment that
helps you make good choices on a day-to-day basis. Achieving perfect control over
your food environment is not the goal, but most people will be able to improve it
greatly just by making an effort to do so. Our program materials provide practical
guidelines to improve your food environment.
Modify the Body Fat Setpoint
Ultimately, one of the primary reasons why diets fail is that the energy homeostasis
system detects fat loss and initiates a program to restore body fat to its initial level [8].
The effects are familiar to many people who have tried to lose fat by calorie restriction
alone: hunger, fatigue, and a preoccupation with food. Ideally, we want a strategy
that will lower the setpoint itself, such that the body ‘wants’ to lose fat. In this
scenario, a person continues to eat to fullness, has a healthy energy level, but total
calorie intake is lower and body fat declines.
In practice, it is difficult to measure whether a particular intervention has altered the
setpoint itself, or reduced body fat by another means. The setpoint has been indirectly
measured in animal studies [61, 62] and in humans [5, 63-65], but data from humans
are sparse.
However, when an intervention causes body fatness to decline
substantially without causing the expected increase in hunger, it is reasonable to
suppose that it has lowered the setpoint. There are many studies in humans that have
suggested strategies for accomplishing this.
The “Paleolithic diet” is a good starting place for this discussion. This is a diet based on
the idea that we are best adapted to the diet of our distant ancestors, prior to
industrialization, and prior to the development of agriculture 10,000 years ago [66].
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 24 The Paleolithic diet focuses on fresh, unrefined foods, including vegetables, meat and
seafood, starchy tubers, fruit, nuts, and eggs.
It excludes processed food, grains,
legumes (beans, lentils and peanuts), and dairy. Researchers have debated the validity
of the assumptions underlying this diet, however we don’t need to resolve that debate
for our purposes. What we will discuss are the controlled trials demonstrating the
effects of the Paleolithic diet on food intake and body fatness, and use this diet as a
jumping off point to demonstrate some useful principles in fat loss.
Paleolithic diet studies have mirrored the growing number of anecdotes from people
who have successfully used this diet as a fat loss tool. From the perspective of fat loss,
the most informative study to date was conducted by Dr. Staffan Lindeberg and his
colleagues at the University of Lund [67].
Researchers assigned 29 overweight,
diabetic or pre-diabetic cardiovascular patients to either 1) a Paleolithic diet, or 2) a
Mediterranean diet, centered around whole grains, legumes, and low-fat dairy. Both
diets caused weight loss and improvements in health, however the Paleolithic diet was
the most effective. In 12 weeks, participants lost 11 pounds, despite the fact that they
were not asked to restrict calories or lose weight. Even more impressively, all 14
participants in the Paleolithic group had normal blood glucose at the end of the study
(compared to 7 of 15 in the Mediterranean group, which is itself impressive).
This weight loss was accompanied by a spontaneous reduction in calorie intake.
Paleolithic dieters consumed less food than the Mediterranean group, but experienced
no greater hunger [68]. This study, among others, suggests that diet quality can
influence the body fat setpoint, resulting in a naturally lower weight that does not
require calorie counting to maintain. Let’s dig deeper.
What is it about the Paleolithic diet that seems to lower the body fat setpoint?
Research has identified a number of factors that may be involved.
The most
straightforward is protein. The Paleolithic diet is high in protein from meat, seafood,
eggs and nuts [66]. A number of controlled trials have shown that even outside the
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 25 context of a Paleolithic diet, high-protein diets facilitate fat loss and the maintenance
of leanness [51-53].
In one particularly interesting study, a group of overweight
volunteers was placed on different diets in a controlled setting where food intake could
be monitored precisely [52]. When moved from a 15 percent protein diet to a 30
percent protein diet (at the expense of fat), spontaneous calorie intake decreased by a
full 441 calories per day, resulting in a loss of 11 pounds over 12 weeks (mostly as body
fat). This was despite the fact that the study was not designed around weight loss,
and the volunteers were not asked to reduce calorie intake.
Animal experiments have suggested plausible mechanisms for this effect. Dietary
protein causes the release of a hormone called glucagon, which promotes satiety [69].
In addition, animal studies have suggested that the amino acid leucine (a component
of protein) acts directly on energy homeostasis centers in the brain, which results in
lower food intake and a reduced body fat setpoint [70].
Calorie density is another factor in the weight loss effect of Paleolithic diets. Many of
the foods we commonly eat today, and which are restricted or excluded on a
Paleolithic diet, are high in calorie density. These include flour-based foods (e.g., bread,
pastries), chips, candy, and added fats and sugars.
These are among the most
commonly consumed foods in the modern US [71]. Liquid calories are a related issue.
Calorie for calorie, liquids such as soda and milk typically provide less satiety than
solids, and sweetened beverages may be one of the primary drivers of fat gain globally
[72]. Sweetened beverages such as cola are highly rewarding and palatable due to the
combination of sugar, texture, and caffeine, and therefore they can be habit-forming if
not addictive in susceptible people.
The Paleolithic diet also restricts food variety. Studies have shown that increasing food
variety increases total calorie intake [18]. As you might imagine, this phenomenon
applies to any diet, not just the Paleolithic diet. Almost any diet in which food choices
are restricted causes weight loss: Paleolithic, vegan, low-fat, low-carbohydrate, the
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 26 banana diet-- you name it. Some of these diets are diametrically opposed to one
another, yet they all cause weight loss (in the “average” person—individual mileage
may vary). This leads to much confusion and conflict between diet gurus, each of
which thinks that the specific factor they have excluded is the key to weight loss.
The Paleolithic diet also encourages simple, natural foods that tend to promote healthy
appetite regulation. It excludes the most highly rewarding, palatable foods, decreasing
the likelihood of eating in the absence of hunger. Researchers have found that the
parts of the brain that regulate body fatness and food reward communicate with one
another extensively [8, 73]. For example, if you haven’t eaten very much food in
several days, you’ll be more motivated to obtain food, and this is the result of
homeostatic circuits acting on reward circuits to increase food-related motivation in an
effort to recover the missing calories [8]. Conversely, reward circuits also influence
homeostatic circuits. What this means in practice is that highly rewarding, palatable
foods may actually increase the body fat setpoint, and eating simpler foods may
decrease it [8, 61, 62, 64, 73, 74]. Therefore, moving away from a diet of highly
palatable foods may make it easier to lose fat because the body ‘wants’ to be leaner.
Simple, natural, whole food meals can be satisfying and taste good, but they do not
include the hyperpalatable creations that line grocery store shelves and fill restaurants.
While the Paleolithic diet can be an effective tool, we do not need to eat a Paleolithic
diet to leverage this phenomenon, but we do have to eat a diet that does not include
modern refined hyperpalatable foods.
Support Digestive Health
Another topic that has received a lot of interest recently is digestive health and its
surprising relationship to body fatness. The digestive tract is a long tube designed to
import nutrients into the body, while excluding non-nutritive substances and
microorganisms. It is lined by a thin layer of cells called the ‘gut barrier’, which is
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 27 responsible for ensuring that the body’s contents remain inside, and unwanted gut
contents remain outside.
The human digestive tract hosts trillions of bacteria,
collectively called the ‘gut flora’. This community of microorganisms help us by
digesting food, synthesizing vitamins, protecting us against pathogens, and providing
nutrients that keep our gut barrier healthy and functional.
While these bacteria
support our health, they must remain on the other side of the gut barrier. If they cross
into the body, or components of them cross into the body, it can reduce metabolic
health and increase fat gain (particularly fatness in the abdominal region) [75, 76].
Therefore it is essential to maintain the health of the gut flora and the integrity of the
gut barrier.
Three important factors that influence gut health are dietary fiber, food sensitivities,
and antibiotics. Just like us, bacteria must eat to survive, and their primary food source
is dietary fiber. When our diet contains sufficient and varied dietary fiber, we provide
our inner ecosystem with the food it needs to thrive. Unfortunately, most people in
affluent societies do not consume sufficient dietary fiber to maximize the health of
their gut flora. For most people, healthy gut function is supported by consuming a
variety of unrefined plant foods, including some or all of the following: vegetables, fruit,
legumes, and whole grains. Experiments in animals and humans have shown that
dietary fiber can prevent fat gain, and even produce modest weight loss and metabolic
improvements [77-80]. Some of this may involve the ability of bacterial fermentation
to improve gut barrier integrity, but research is ongoing.
Food sensitivity may be another issue in gut barrier integrity. Many people are sensitive
to common foods including milk (lactose and/or casein) and wheat (gluten and/or
fructooligosaccharides). In susceptible people, these foods can cause the abnormal
growth of bacterial species in the digestive tract and/or a reduction of gut barrier
integrity, potentially exacerbating fat gain and poor health [81, 82].
Therefore,
identifying and eliminating food sensitivities may help reduce abdominal fat and
improve health.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 28 Since the gut microbial community is predominantly composed of bacteria, and
antibiotics are designed to kill bacteria, it may not come as a surprise that antibiotics
cause severe, durable changes in the gut ecosystem [83].
Although research is
ongoing, at least two studies in humans have shown that certain antibiotics may lead
to weight gain [84, 85], and this is consistent with the fact that low-dose antibiotics are
sometimes used to fatten livestock.
Frequent antibiotic use in childhood is also
associated with a greatly increased risk of inflammatory bowel disease (e.g., Crohn’s)
[86], potentially reflecting an adverse effect of antibiotics on gastrointestinal health.
Antibiotics may have more drawbacks than originally appreciated.
However, they
remain an extraordinary class of life-saving drugs, and any decision related to
antibiotic use should be carefully discussed with a doctor.
Beyond diet, sleep and physical activity also play an important roles in body fatness,
and some of this may relate to effects on the energy homeostasis system. Let’s take a
closer look at these two topics.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 29 IDEAL WEIGHT & SLEEP
As discussed previously, the recent steep increase in obesity prevalence likely results
from behavioral and environmental changes [87, 88]. Since the proportion of the
population that has become overweight or obese has risen so rapidly over the last 30
years, scientists have been interested to determine what factors have changed during
this period of time to understand what may be driving this phenomenon. Perhaps
surprising to some, a strong association between insufficient sleep and weight gain has
been consistently demonstrated. This is notable because as you’ll see in the next
section, population sleep times have decreased in parallel with the increase in obesity
prevalence. But how significant is this effect? An analysis conducted by Jean-Philippe
Chaput and colleagues [89] provided insight into this question by examining nine risk
factors for obesity over a six year period. They found that sleep duration and eating
behavior were among the most powerful predictors of weight gain.
Another example that illustrates the connection between sleep and weight comes
from twin studies showing that if one twin tends to sleep less than the other, he or she
also tends to have a higher BMI [90]. This was also observed among identical twins—a
particularly significant finding because identical twins are genetically identical to one
another, therefore any differences in body weight must result from environmental
factors.
In addition, a systematic literature review including data from 634,511
subjects across all ages (2 to 102yrs) and genders found a consistent increased risk of
obesity among short sleepers in both children and adults [91].
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 30 The association between chronic sleep restriction and obesity is likely to operate in
both directions: poor sleep increases the risk of weight gain, and weight gain worsens
sleep [92], as approximately 50% of obese people complain about the quality of their
sleep [93]. To date, 81 of 89 observational studies have found a significant association
between short sleep duration and weight gain. A complete fat loss program will not
ignore these findings.
How Much Sleep Are We Getting?
Over the past 50 years, self-reported sleep duration in the United States has decreased
by nearly two hours [94-98]. That’s a 20 percent decrease, or the equivalent of losing
one complete night of sleep each week! In the 1960s, the average self-reported sleep
duration was 8.5 hours per night. In 2006, it was 6.8 hours on weekdays and 7.4 hours
on weekends [99]-- and the situation appears to be getting worse. Recently, the
National Sleep Foundation reported that in the last 10 years, there has been a 53%
increase in people reporting less than 6 hours of sleep a night [100].
Why Are We Getting Less Sleep?
Sleep time has declined for several reasons. In particular, technologies like television,
computers, cell phones, and tablets keep us engaged and alert late into the night.
Later, we’ll review how artificial light can mask sleepiness, and cause a shift in our body
rhythms that disrupts our natural sleep-wake cycle (see section titled “Circadian
Rhythms”). In fact, new technologies allow us to take work with us anywhere, including
the bedroom at night.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 31 Another reason we voluntarily curtail sleep duration is to make more time for our
personal lives [101]. The modern environment presents many demands and vices that
can become tradeoffs with our health. To some degree, your health will be determined
by your ability to establish excellent sleep hygiene in the face of these modern forces.
Our tools and guidelines show you how to maintain a healthy sleep-wake routine-- one
that will support your goal to achieve and maintain your ideal weight.
Potential
Causes
of
Weight
Gain
Due
to
Insufficient Sleep
There is considerable evidence in animals and humans suggesting that insufficient
sleep (both quality and quantity) has adverse effects on metabolism. Insufficient sleep
alters appetite-regulating hormones and affects how the body handles energy
supplies, like fats and carbohydrates. In 2012, researcher Josie Broussard and
colleagues [102] reported on whether sleep restriction reduced the ability of the
hormone insulin to properly regulate fat tissue. Before her research, it had been shown
that insufficient sleep increases the risk for insulin resistance, type 2 diabetes, and
obesity, yet a direct link between sleep restriction and changes in fat tissue metabolism
had never been demonstrated. In Dr. Broussard’s study, subjects spent time in two
conditions sequentially. In the first condition, they spent 8.5 hours in bed each night for
four nights. In the second condition, they were only allowed 4.5 hours per night of
sleep for four nights (yawn!). After both conditions, researchers collected fat tissue
biopsy samples. They found that sleep restriction made fat cells resistant to insulin—in
other words, decreasing insulin’s ability to activate key steps within the cell necessary
for this important hormone to exert its function. Since insulin action on fat cells is a
normal part of healthy metabolic functioning, this suggests a specific mechanism by
which insufficient sleep can predispose to metabolic problems such as diabetes.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 32 Sleep and Inflammation
Inflammation is a form of immune system activation that is important for pathogen
defense and healing, but can be detrimental when it is chronically elevated. Shorter
sleep duration associates with increased markers of inflammation [103, 104]. When
chronically elevated, some inflammatory signals interfere with normal cell signaling
and metabolism. For example, elevated inflammatory signals may cause insulin
resistance and dysfunction in body fat control centers in the brain [105, 106].
Additionally, certain inflammatory signals make you feel sleepy and fatigued-- think of
the lethargy you feel when you’re sick. Elevated inflammatory signals that are involved
in the immune process cause this low-energy feeling. Now consider how insufficient
sleep – mediated in part through increased inflammatory markers – could cause
reduce physical vitality, promoting less habitual physical activity. This may decrease
interest in standing, going for a walk, and exercising, but also less obvious forms of
physical activity such as fidgeting. On average, we are getting 20% less sleep than we
were 50 years ago, and this degree of sleep loss is correlated with significant increases
in inflammatory signals. If insufficient sleep becomes a lifestyle pattern, weight gain is
not necessarily an immediate or automatic outcome, but available evidence suggests
that risk for weight gain may increase due to reduced physical activity and impaired
metabolic function.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 33 Circadian Rhythms & Body Weight
Many behaviors, and physiological functions of the body, show rhythmic 24 hour
activity patterns called “circadian rhythms.”
Sleep-wake behavior is an obvious
example: we are generally awake for 16 hours of the day and asleep for roughly 8
hours at night, and this cycle repeats day after day. Circadian rhythms are regulated by
biological “clocks” in our tissues, which influence cellular activity differently at different
points in the 24-hour period [107]. In order for biological processes to function
effectively at the level of the whole organism, these tissue-specific circadian clocks
must be synchronized with one another so that tissues function in harmony. When
tissue cycles are not synchronized with one another, dysfunction occurs.
The synchronization of tissue clocks throughout the body takes place as follows: light
enters the eye and influences the activity of the “master clock,” which resides in a part
of the brain called the suprachiasmatic nucleus. The master clock then sets the
rhythms of tissue clocks throughout the rest of the body [108].
Now, think about how artificial light can wreak havoc on this process. The brain tries to
coordinate its rhythms with the light-dark cycle, but artificial light tricks the master
clock into thinking it is still daytime even long after the sun has set. Not only does light
cause your brain to think it is daytime when it is actually night - initiating a signal to
adjust the body’s clocks to an improper circadian cycle – light also activates the brain,
making you feel more alert. There term “iPad insomnia” encapsulates this problem.
People commonly use light-emitting devices in bed “until they feel sleepy.” However,
the light entering the eye is alerting, and it masks the drive to sleep that would
otherwise occur if it were dark. Artificial light at night not only causes our circadian
rhythms to shift unnaturally, it also masks sleepiness. These are two major reasons
why the quality and quantity of our sleep suffer (as well as next-day wakefulness).
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 34 People who do shift work – think of those who do day shifts and night shifts within the
same week - are chronically “desynchronized.” Their circadian rhythms are always
being pulled in different directions, and because it takes several days for our rhythms
to adjust to a new schedule, these people live in a state of “perpetual jet lag”. Because
circadian rhythm synchronization is so critical for health, it’s not surprising that shift
work is associated with widespread tissue dysfunction including increased abdominal
circumference
and
BMI
[109,
110],
as
well
as
greater
incidence
of
cardiovascular disease, diabetes, and obesity [111]. The timing of sleep is as important
as the duration of sleep. We’ll help you ensure that both are optimized.
Insufficient Sleep, Food Intake, and Fat Loss
Sleep restriction studies generally show increases in appetite, and some studies have
also demonstrated a small increase in the preference for carbohydrate-rich foods [94,
112]. In one study, subjects ate 22 percent more calories the day following sleep
deprivation. The study also showed that these subjects didn’t rate the pleasantness of
food differently, nor did they have an increased desire to eat, yet they still ate more
than people who were not sleep restricted. They felt tired but not hungrier than usual,
yet they ate nearly a quarter more calories over the course of the day. These changes
can take place beyond our awareness but can lead to very real consequences for our
weight and health.
Sleep restriction also interferes with fat loss during a reduced-calorie diet. A wellcontrolled studied by Nedlecheva and colleagues demonstrated this effect clearly. In
this study, overweight volunteers followed a calorie-restricted diet for two weeks under
normal (8.5 hours/night) or sleep restricted (5.5 hours per night) conditions. The
amount of weight lost during each treatment was similar, but the composition of the
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 35 weight lost differed considerably. Under normal sleep conditions, fat represented 57%
of the lost weight. In the sleep restricted condition, fat constituted only 26% of the lost
weight, with the rest of the weight loss occurring in lean tissue [113]—an extremely
undesirable outcome. Together, these results show that sleep restriction may increase
food intake, increase craving for carbohydrate foods, and impair fat loss.
Cognition, Sleep, and Weight Gain
When a person gets an insufficient amount of sleep night after night, daytime
alertness deteriorates progressively for the duration of the sleep restriction period.
Remarkably, one week of partial sleep restriction (4 hours of sleep per night) impairs
alertness to the same degree as 48 hours of complete sleep restriction! This tells us
that the effects of sleep loss accumulate over time [114, 115]. As expected, other
measures of mental performance – aside from alertness - are impaired as well,
including decision making, memory, and mood [116-134].
Executive Functions
The term “executive function” refers to higher cognitive functions that allows us to
plan and achieve goals. An executive act lets us influence future outcomes by
regulating current behaviors [135]. To lose weight (or achieve any goal), you must
conceive of your goal, retain it in memory, identify a strategy to achieve it, modify your
behavior according to your strategy, and inhibit behaviors that interfere with your goal
[136]. These cognitive abilities strengthen from birth to adulthood. Think of the
characteristic impulsiveness of toddlers and teenagers—they have a low capacity to
perform long-term goal-oriented behaviors. Indeed, as we age into our young adult
years, our ability to delay gratification increases [137]. In other words, we have an
increased ability to say no to an immediately desirable stimulus in order to fulfill a
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 36 long-term goal, for example, saying no to a bowl of ice cream when you’re trying to
lose weight.
To study executive functioning, researchers use “time discounting” tasks, which
measure how the perceived value of a gift changes based on how long an individual
has to wait to obtain it. For example, most people consider receiving $100 today more
valuable than receiving $100 one year from today. Time discounting refers to the
decrease in the value of the $100 gift as it moves further into the future.
Experimentally measuring time discounting assesses a person’s willingness to
postpone receiving an immediate reward in order to gain additional benefits by
waiting. Drug addicts significantly discount the future [138]. For example, if you were
to ask a heroin addict “would you like $5 now or $1000 in a month,” the likelihood that
she would accept the $5 now is greatly increased compared to a non-addict.
The ability to delay gratification and time discounting are closely related, because they
both reflect the value that a person places on the future relative to the present. It is
not difficult to think of examples where this might influence body weight and health:
should you eat a pastry now (immediate benefit), or avoid eating the pastry in order to
pursue your goal of fat loss (long-term benefit). The ability to delay gratification has
been shown to predict the likelihood of engaging in a range of health-related behaviors
such as regular exercise and healthful eating patterns [139-141]. A weaker ability to
delay gratification is associated with a higher risk of developing obesity over time [142].
The reduced ability to delay gratification in order to achieve a future goal can be
thought of as a form of impulsivity or risk taking behavior, and this concept is critical
when considering our health.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 37 This brings us back to sleep, because the mind alters how it makes decisions when it’s
sleepy. In fact, sleep restriction makes us more impulsive and more likely to engage in
risky behaviors [143]. During gambling tasks, a sleep-deprived subject will take risks
more frequently and will also take larger risks [144]. Sleep-deprived subjects also
exhibit a phenomenon called ‘effort discounting,’ meaning they are less willing to make
an effort toward something they want but have to work for. Think about how these
alterations in decision-making relate to your lifestyle. If you are sleep deprived, you’re
more likely to say yes to the candy bowl at work, even when you know it’s not in your
best long-term interest. You’re more likely to say yes to the dessert cart even though
you know it conflicts with your weight loss goal. You’re less likely to exercise, and
ironically, you’re less likely to go to bed on time, even if these are things that are
important to you.
Sleep Loss and Increased Pleasure Eating
Not only does sleep loss make us more impulsive and more likely to engage in risky
behaviors, it also changes how the brain responds to food stimuli [145]. When sleepdeprived research subjects view high calorie foods, their brains respond differently than
those of normal sleepers [146]. Acute sleep loss enhances the brain’s response to
pleasurable food stimuli and increases the drive to eat – regardless of whether or not
sleep deprivation increases actual hunger. As a result, these studies typically show
increased food consumption of about 300 calories per day. If you recall our earlier
discussion, we’re eating about 350 calories more per day than we were in 1970, and
the best available mathematical models suggest that this increase in calorie intake is
sufficient to account for the obesity epidemic. This is interesting in light of the fact that
we’re currently sleeping 20 percent less than we were 50 years ago.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 38 Sleep Conclusion
Sleep loss has direct, measurable physiological consequences that undermine healthy
behaviors, impair metabolism, and probably increase the risk of fat gain and health
complications over time. Chronic sleep deficiency impairs our body’s ability to manage
its energy stores effectively, reduces our daily alertness level making us less mindful of
how much food we eat, reduces our ability to delay gratification, and increases
pleasure processing in response to food.
We make more than 200 food-related decisions per day, and each decision is an
opportunity to align with or stray from your healthy eating strategy and fat loss goal
[147].
In an environment where food is always present, insufficient sleep can
encourage the regular overconsumption of calories, even without our conscious
awareness. A sleep-deprived brain is more likely to become a casualty of the fattening
modern environment. If your goal is to achieve and sustain a certain level of leanness,
good sleep is one of the most powerful weapons in your arsenal.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 39 IDEAL WEIGHT AND
PHYSICAL ACTIVITY
Most of us do not require much physical activity to go about our daily lives. In fact, to
make a living, many of us are required to sit at a desk for most of the day. But physical
inactivity is not a behavior to which we have adapted as a species. In societies not so
heavily influenced by modern technology, like hunter-gatherer societies, survival
requires constant movement: the search for food and water, evasion of dangerous
creatures, and maintenance of shelter and clothing. Researchers have used GPS
technology to follow members of some of these societies, and found that they typically
walk roughly 6 miles, and run an additional mile, each day. They generally perform
moderately strenuous activity daily, but they also typically rest for a day after
particularly strenuous activity. As they move through irregular terrain they are
frequently required to sprint, jog, climb, throw, carry, and jump intermittently
throughout the day [148].
Several interesting aspects of the hunter-gatherer lifestyle stand out, including the
type and quantity of movement, the patterns of activity and rest, and how activity is
spread over the day. Even for those who are physically active in the modern world,
many cluster physical activity into a workout, followed by long periods of inactivity. As
Marc Hamilton – a Professor at Pennington Biomedical Research Center, Louisiana State
University – wrote, “exercise is not the perfect antidote for sitting.” In other words,
research suggests that prolonged inactivity itself may be harmful even for a physically
fit person-- exercising for 20-60 minutes may not necessarily allow you to be sedentary
for 15 hours continuously without negative consequences. We may benefit from
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 40 finding ways to stand and walk more often throughout the day. In fact, a new
subspecialty of biomedical research has emerged to study the consequences of
sedentary behavior: it is called inactivity physiology [149]. This is an important
emerging field of health research because as a culture we are becoming increasingly
sedentary, and there may be unique consequences associated with sitting too much.
Weight gain may be one of those consequences.
Stand and Walk
How much time per day do you spend sitting? The Centers for Disease Control and
Prevention defines sedentary behavior as “not engaging in any regular pattern of
physical activity beyond daily functioning” [150]. This is equivalent to waking up,
driving to work, sitting at work all day, driving home, and watching television or reading
until bedtime. There are large differences in the physiologic state created by a day of
sitting (inactivity) vs. a day of standing (non-exercise activity). Evidence consistently
shows that prolonged bouts of sedentary behavior increase the amount of fat
(triglycerides) circulating in your blood – a marker of metabolic problems and a risk
factor for cardiovascular disease [151].
Even sitting for a single afternoon brings you measurably closer to the metabolic state
of type 2 diabetes—decreasing tissue responsiveness to the blood-sugar regulating
hormone insulin (fortunately, this is reversible) [151].
When standing or walking
slowly, postural muscles gently contract, and this muscle activity contributes positively
to your metabolic health. For example, simply transitioning between sitting and
standing activates the enzyme lipoprotein lipase in muscle tissue, which takes fat out
of the blood to fuel muscular contraction [149, 152, 153]. Low levels of lipoprotein
lipase are associated with lower fat consumption by muscle tissue, and are also
associated with high blood pressure, metabolic syndrome, and a higher incidence and
severity of coronary artery disease [153-158].
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 41 The good news is that simply standing more can increase lipoprotein lipase activity
several-fold, which is an important reason why we see numerous health benefits from
increased standing, including likely benefits for weight control [159]. It’s easy to think
that if you want to lose weight, you should exercise more. This is what our culture
promotes. It’s less intuitive to think that behaviors as mundane as standing and
walking may benefit you as much as exercise. Yet standing is currently a hot topic at
physiology and health science conferences, and there is considerable excitement
among researchers that sedentary behavior may be a major missing piece in the
puzzle of health disorders like obesity, diabetes, and cardiovascular disease.
Compared to sitting, physical activity of any kind expends calories. A study published in
the prestigious journal Science found that people who are lean tend to be physically
active for over 50 percent of the day, whereas people who are obese tend to be active
less than 40 percent of the day [160]. This presents us with a chicken-or-egg question:
did physical inactivity or obesity come first? In fact, each factor probably contributes to
the other. However, in combination with other evidence, for example the association
between driving miles and increased incidence of obesity [161, 162], the data suggest
that inactivity may indeed contribute to fat gain. As technology progressively removes
the need for physical activity from our lives, we bear the consequences as our culture
becomes increasingly overweight.
People in sedentary jobs burn up to 75 percent fewer (700-1600 kcals less) calories per
day than employees who hold manual labor jobs [163]. But how many more calories
do you expend simply standing versus sitting? The absolute difference in energy
expenditure is modest, around 10 percent, but carried out over the course of the day,
this can lead to meaningful differences in total energy expenditure (for a 170 pound
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 42 lean male, this is about a 300 kcal difference for one day). Compared to a week of
sitting at work, simply standing at work expends a number of additional calories
roughly equal to what you would expend if you performed several intense cycling
classes!
Dan’s Plan recommends standing for at least 50 percent of your time awake on most
days. Currently, there is no definitive evidence to support 50 percent as superior to 40
percent or 60 percent, but we feel based on existing evidence that 50 percent is a
useful guideline. At any point of the day you can ask yourself, “have I been standing for
approximately half my day?” If the answer is “no,” you can then alter your behavior
accordingly. It is challenging to accurately measure how much a person stands or sits.
However, there are new products coming onto the market with the potential to help.
One of these new products is called Lumoback, which measures posture while sitting
and standing. Check it out, it may give you more awareness over how much you’re
sitting, and what your posture is like while sitting and standing.
Many offices now offer or allow standing desks. You do not need to spend your entire
day on your feet, but periodically alternating between sitting and standing is
comfortable, practical, and healthy. If you are new to standing at work, you may find it
uncomfortable at first. It is common for people to experience soreness during the first
several days on their feet. To minimize discomfort, transition slowly to more frequent
standing. Allow yourself to be guided by how you feel. It may take your body time to
acclimate, but eventually you may find it preferable to sitting exclusively.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 43 Walking
It has been observed that adults who take 7,000 to 13,000 steps per day are a healthy
segment of the population [164, 165]. Once again, this is a chicken-and-egg problem,
because we can’t know whether healthy people walk more, or walking makes you
healthy. As before, both are probably true, however there is good evidence suggesting
that walking regularly improves health.
In fact, the benefits of walking can be
substantial. One study showed that walking 2 miles a day was as effective as jogging 3
miles a day for improving metabolic health [166]. Other studies have shown that
increasing daily steps minimally from 2,000 to 4,000 per day correlates with a decrease
in measures of obesity such as waist circumference and BMI [167]. While 4,000 steps a
day is still classified as sedentary, this shows that health benefits can occur along the
entire step spectrum.
However, the positive effects of walking are fleeting. When active subjects who
average over 13,000 steps per day suddenly reduced their step number to less than
5,000 per day for three days (a step level representative of the average American),
these otherwise fit individuals began to show higher blood sugar spikes after meals—a
hallmark of progression toward type 2 diabetes. Worse, post-meal spikes increased by
25 percent during each successive day of low step activity. These blood sugar changes
happened prior to any changes in fitness or body fat levels; they were a direct result of
inactivity. Again, this is indicative that our bodies work better with movement and that
movement is medicine for our bodies.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 44 General Classification for Daily Steps
CLASSIFICATION
DAILY STEPS
Sedentary
<5,000
Low active
5,000-7,499
Moderate active
7,500-9,999
Active
≥10,000
Highly active
>12,500
If your lifestyle includes a lot of sedentary time, you can benefit meaningfully from
adding low-to-moderate intensity activity into you daily routine. Non-exercise activity
is important for your health. Don’t attempt to replace a deficiency of non-exercise
activity with a few exercise sessions a week. Likewise, don’t abandon traditional
exercise because you are standing and walking more. Both exercise and non-exercise
physical activity support health, so continue to find ways to make your lifestyle rich
with movement. The feedback provided by physical activity trackers such as the Fitbit
gives you constant awareness—and therefore more control—over this important
behavior.
Exercise
Exercise is a form of controlled stress. The right amount of stress strengthens the body,
but too much stress weakens it. The evidence suggests that there is a volume of
physical activity that one should aim to attain on a weekly basis for the purposes of
health and body weight control. We describe these volume criteria in our Ideal Weight
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 45 Program materials, as defined by the physical activity guidelines of the US Department
of Health and Human Services. Once you surpass the minimum exercise threshold for
health, athletic performance may continue to improve with increasing exercise, but the
health benefits show diminishing returns on investment. This concept should be
motivating. You get most of the health benefit from a modest amount of exercise; you
can choose to do more if you enjoy it, have time, and are inspired to perform well at
athletic endeavors. You don’t need to exercise like a professional athlete to achieve
health through physical activity.
In light of the idea that a bout of exercise provides a dose of stress, a particular
exercise dose, plus a particular interval of rest, can either weaken you, maintain fitness,
or improve fitness. Without sufficient physical stimulation, physical abilities diminish,
muscles atrophy, bones weaken, and organs like the heart and vascular system
become at risk for impaired function. Sufficient rest is the other side of the equation,
and equally important. Excessive exercise without sufficient rest decreases physical
vitality and may even increase health risks.
The most effective dose of exercise is highly dependent on your current physical
condition. Have you been training regularly? Has your nutrition and sleep been
adequate, and have your stress levels been low over the last few months, weeks, or
days? The optimal dose of exercise is very personal and dependent on the ‘you’ that
exists right now. Consider the analogy of sun tanning. If you haven’t been in the sun for
months, you won’t tan faster by getting more sun that you can handle. The solar stress
will simply cause your skin to ‘burn’. You will then have to avoid sunlight for a period of
time before resuming sun exposure. In contrast, gradually increasing sun exposure
day after day, with appropriate ‘rest’ periods between exposures, causes the skin to
tan, resulting in a progressively higher sun tolerance. The fitness and health benefits of
exercise operate on a similar principle.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 46 If you’re new to a particular physical training style (for example, strength training), an
appropriate training quantity to maximize your rate of improvement might be onethird (or less) the quantity of a person who is acclimated to that training style.
Unfortunately, many people try to perform advanced routines prematurely and make
limited progress, suffer injury, or give up entirely. It is important to remember that high
levels of physical performance are not necessary for health, so from a health
standpoint, there is no reason to give up because you have not achieved a high
performance level. To pursue health, make your exercise routine “organic.” Do what
feels right, choose whatever you enjoy, be spontaneous, use your whole body, and
perform training sessions at least twice per week (in addition to the low intensity
activity you do on a daily basis, like standing and walking).
Exercise and Weight Control
But does exercise help you lose weight? The short answer is yes. Exercise stimulates
healthy metabolic control of energy substrates such as fat and carbohydrate. As
described above, this effect occurs with a modest level of activity. The ability of
physical activity to lower chronic inflammation may also be a mechanism by which
exercise helps control weight levels. Chronic inflammation may decrease the sensitivity
of the control systems that regulate energy reserves. As energy reserves increase in the
form of stored body fat, the control over appetite may become progressively less
accurate increasing the likelihood of further weight gain. Fortunately, both aerobic
exercise and resistance training have been shown to lower inflammation in people who
are overweight or obese [168]. In animal models, exercise opposes fat gain in the face
of a fattening diet by maintaining the function of the energy homeostasis system that
unconsciously regulates body fatness [169, 170]. In other words, regular exercise helps
with weight control by supporting the function of the energy homeostasis system in
the brain.
www.dansplan.com, 2013 Ideal Weight Program Version 2.0.1 47 Exercise also burns calories. It has been said that exercise also increases hunger,
negating the increase in calorie expenditure. This is true to some extent. New research,
however, shows that the calorie expenditure of exercise is not fully compensated by
increases in calorie intake in the ‘average person’ [171]. As described earlier, eating is
influenced by multiple neural systems and one of those systems – the pleasure /
reward system - triggers impulsive eating and overeating. There is an emerging
understanding that regular physical activity modifies the brain’s response to food,
weakening the drive to overeat, while simultaneously enhancing cognitive resources
that strengthen goal-oriented behavior [171, 172]. Regular exercise enhances what is
referred to as “top-down inhibitory control,” which means that your cortex has an
increased ability to prevent overeating without you even noticing.
Regular exercise helps your body process energy substrates like fats and
carbohydrates, reduces inflammation, and strengthens the brain’s ability to prevent
overeating. There are many reasons to exercise, and weight control is one of them.
Closing
We hope this information strengthened your understanding of the factors controlling
body fat and how you can manipulate them to your advantage. The program materials
on Dan’s Plan are designed to help make it easier for you to implement this knowledge
in your life so that you may achieve and sustain your ideal weight.
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