Q: How Many Calories Does a Pound
of Muscle Burn?
A.
Some fitness books and many fitness articles have mistakenly stated that
each added pound of muscle burns as many as 50 extra calories per day. This is
usually stated with the encouragement to build a few pounds of muscle so that
you can raise your metabolism and burn more calories 24/7. While this is
generally good advice, the truth is that the metabolic rate for muscle has been
calculated at about 5-6 calories per pound by Dr. Claude Bouchard (1).
However, it is probably important to distinguish between the resting metabolic
rate of a pound of sedentary muscle and muscle that is being actively trained.
Resistance training studies have shown a much greater increase in metabolic
rate per pound of muscle gained (2, 3), which strength expert, Dr. Wayne
Westcott, explains as resulting from an increase in protein turnover in all of the
muscle mass trained (4, 5).
In other words, if you are training hard on a regular basis you’re not just adding
muscle, you are increasing the protein turnover in all of the muscle being worked
which would have an increased metabolic cost beyond the energy demands of
the workout. Results from the studies Dr. Westcott has looked at suggest that
this increased metabolic cost may amount to about a 7% greater caloric output
each day. So if you were burning 1800 calories a day before you started lifting
weights regularly, you may burn over 1920 calories a day now (1800 + 126 (7%)
= 1926). Since such lifting is usually accompanied by around at least a 2-3lb
increase in lean weight, that is how people got the idea that each pound was
burning an additional 40-60 calories a day, though that isn’t what is really
happening. That kind of thinking assumes that the only training-induced change
is the addition of new muscle tissue, which is entirely responsible for the
metabolic increase. In reality, it is far more likely that all of the skeletal
muscle affected by the strength-training program experiences an increase
in protein turnover, meaning that there is a slight increase in metabolism in
all of the trained muscle. Since about half of the average individual’s lean
weight is skeletal muscle, we are talking about a slight increase in metabolism
over about 50-80lbs of muscle mass. Even if each pound of that muscle is
only burning an extra 1.5 calories per day that means the metabolism will
rise anywhere from 75-120 calories extra per day. That’s the equivalent of
an extra 2 miles of walking every day!
A slight rise in metabolism over a lot of muscle = significant calorie burn
Let me show you how it works:
If a 155-pound man with a resting metabolic rate of 1,600 calories per day has
approximately 62 pounds of skeletal muscle, and each pound uses 6 calories per
day at rest, then the contribution to his resting metabolism is about 372 calories
(62 pounds of muscle x 6 calories per pound = 372 calories). If that sounds low,
recognize that not all lean weight is muscle. The greater portion of your
metabolic rate comes from the work of your internal organs which burn in excess
of 20 calories per pound!
Anyway, if the strength-training program adds 3 pounds of muscle tissue
(probably mostly glycogen and water) for a total of 65 pounds of skeletal muscle,
and if each pound of trained muscle now uses 7.5 calories per day at rest (a 1.5
calorie increase), then the new contribution to his resting metabolism is about
488 calories (65 pounds of muscle x 7.5 calories per pound = 487.5 calories).
This represents about 116 additional calories expended each day at rest (372
calories to 488 calories = 115 calories), which increases his resting metabolic
rate by approximately 7.2 % (1,600 calories per day x 7.2 % = 115 more
calories). This metabolic increase is consistent with the research findings at both
Tufts University and the University of Maryland as you can see in the chart
below:
Comparisons of Research Studies:
Research Study
Strength Training
Program
Training
Frequency
Training
Duration
Change
Muscle Tissue
Change Resting
Metabolism
Campbell, et al. Tufts
University
4 exercises; 3 sets; 812 reps
3 times per
week
12 weeks
+3.1 lbs.
+6.8%
Pratley, et al.
University of
Maryland
14 exercises; 1 set/2
sets; 10-15 reps
3 times per
week
16 weeks
+3.5 lbs.
+7.7%
So a basic weight training program performed just three days a week can
produce, on average:
1. A little over 3 lbs of lean weight in 3-4 months
2. An increase in resting metabolism by about 7%.
It makes sense that muscles that are in the process of building and repair would
have a more active metabolism than muscles that are more sedentary. Research
from Dr. Wayne Westcott indicates that regular strength training elicits an
increased rate of muscle protein synthesis,(6) which likely explains the 7%
increase in resting metabolism each day. In any case, it is more reasonable than
assuming that new muscle tissue uses 40 or even 50+ calories per pound per
day, or that trained skeletal muscle still uses only 5-6 calories per pound per day.
Bottom Line: Sedentary muscle appears to burn about 5.7 to 5.9 calories
per pound each day. Weight trained muscle appears to burn about 7.2 to
7.4 calories per pound each day (increasing metabolism by about 7% a
day).
Now you know… J
Stoking the metabolism with more weight training exercise,
-Tom Morrison
Fitness Coordinator, BWC
Reference Sources:
1. Westcott, Wayne. Increased Muscle=Increased Resting Metabolic Rates =
Weight Loss. Full article found here:
http://www.fitcommerce.com/blueprint/increased-muscle-=-increased-resting-
metabolic-rates-=-weightloss_page.aspx?pageid=744&tabindex=5&portalid=2&cpid=1380-1
2. Campbell, W., Crim, M., Young, V. and Evans, W. 1994. Increased energy
requirements and changes in body composition with resistance training in older
adults. American Journal of Clinical Nutrition, 60: 167-175.
3. Pratley, R., Nicklas, B., Rubin, M., Miller, J., Smith, A., Smith, M., Hurley, B.,
and Goldberg, A. 1994. Strength training increases resting metabolic rate and
norepinephrine levels in healthy 50 to 65 year-old men. Journal of Applied
Physiology, 76: 133-137.
4. Pikosky, M., Faigenbaum, A., Westcott, W., and Rodriguez, N. 2002. Effects of
resistance training on protein utilization in healthy children. Medicine and Science
in Sports and Exercise, 34 (5): 820-827.
5. “Why the Confusion on Muscle and Metabolism?,” Wayne Westcott,
PhD. http://www.ssymca.org/pdf/Health_Articles/Why_The_Confusion.pdf
6. Pikosky, M., A. Faigenbaum, W. Westcott and N. Rodriguez. Effects of
resistance training on protein utilization in healthy children. Medicine and Science
in Sports and Exercise 34 (5): 820-827, 2002.