ORIGINAL INVESTIGATION
A Randomized Trial of Improved Weight Loss
With a Prepared Meal Plan in Overweight
and Obese Patients
Impact on Cardiovascular Risk Reduction
Jill A. Metz, PhD; Judith S. Stern, ScD, RD; Penny Kris-Etherton, PhD, RD; Molly E. Reusser, BA;
Cynthia D. Morris, PhD; Daniel C. Hatton, PhD; Suzanne Oparil, MD; R. Brian Haynes, MD, PhD;
Lawrence M. Resnick, MD; F. Xavier Pi-Sunyer, MD; Sharon Clark, PhD; Leslie Chester, MPH;
Margaret McMahon, MN; Geoffrey W. Snyder, MS; David A. McCarron, MD
Objective: To assess the long-term effects of a prepackaged, nutritionally complete, prepared meal plan
compared with a usual-care diet (UCD) on weight loss
and cardiovascular risk factors in overweight and obese
persons.
Design: In this randomized multicenter study, 302
persons with hypertension and dyslipidemia (n = 183)
or with type 2 diabetes mellitus (n = 119) were randomized to the nutrient-fortified prepared meal plan
(approximately 22% energy from fat, 58% from carbohydrate, and 20% from protein) or to a macronutrientequivalent UCD.
Main Outcome Measures: The primary outcome measure was weight change. Secondary measures were
changes in blood pressure or plasma lipid, lipoprotein,
glucose, or glycosylated hemoglobin levels; quality of life;
nutrient intake; and dietary compliance.
Results: After 1 year, weight change in the hypertension/
dyslipidemia group was −5.8 ± 6.8 kg with the prepared
meal plan vs −1.7 ± 6.5 kg with the UCD plan (P,.001);
for the type 2 diabetes mellitus group, the change was
−3.0±5.4 kg with the prepared meal plan vs −1.0±3.8 kg
R
The affiliations of the authors
appear in the acknowledgment
section at the end of the article.
with the UCD plan (P,.001) (data given as mean±SD).
In both groups, both interventions improved blood pressure, total and low-density lipoprotein cholesterol levels, glycosylated hemoglobin level, and quality of life
(P,.02); in the diabetic group, the glucose level was reduced (P,.001). Compared with those in the UCD group,
participants with hypertension/dyslipidemia in the prepared meal plan group showed greater improvements in
total (P,.01) and high-density lipoprotein (P,.03) cholesterol levels, systolic blood pressure (P,.03), and glucose level (P,.03); in participants with type 2 diabetes
mellitus, there were greater improvements in glucose
(P =.046) and glycosylated hemoglobin (P,.02) levels.
The prepared meal plan group also showed greater improvements in quality of life (P,.05) and compliance
(P,.001) than the UCD group.
Conclusions: Long-term dietary interventions induced
significant weight loss and improved cardiovascular risk
in high-risk patients. The prepared meal plan simultaneously provided the simplicity and nutrient composition necessary to maintain long-term compliance and to
reduce cardiovascular risk.
Arch Intern Med. 2000;160:2150-2158
obesity and overweight in the United States
are at an all-time high, affecting an estimated 97 million adults, or roughly 55%
of persons aged 20 years or older.1 The
medical risks of excess body weight are
well documented, with primary risk manifest in the morbidity and mortality associated with cardiovascular disease and type
2 diabetes mellitus. For overweight individuals with or at high risk of developing
these conditions, weight reduction remains the first-line treatment strategy; even
modest weight loss has been shown to decrease plasma lipid levels and high blood
pressure and, in diabetic patients, to imATES OF
(REPRINTED) ARCH INTERN MED/ VOL 160, JULY 24, 2000
2150
prove glycemic control.2-4 However, realization of the health benefits of weight loss
requires long-term compliance with therapeutic diets, and it is well established that
the difficulties inherent in dietary compliance are a major cause of the failure of
most weight reduction efforts.
The Cardiovascular Risk Reduction
Dietary Intervention Trial was undertaken to evaluate the effects on weight loss
and cardiovascular disease risk factors of
a nutrient-fortified prepared meal plan
compared with a self-selected usual-care
diet (UCD). The meal plan comprises various foods and snacks formulated to meet
the myriad of dietary guidelines of national health organizations specific for re-
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PATIENTS AND METHODS
DESIGN
Baseline Period
This randomized clinical trial of a prepared meal plan was
conducted in 2 separate cohorts: persons with hypertension and dyslipidemia or persons with type 2 diabetes mellitus. It was conducted at 5 university-based medical centers, including Oregon Health Sciences University, Portland;
Pennsylvania State University, University Park; St Luke’s/
Roosevelt Hospital, New York, NY; University of Alabama
at Birmingham; and University of California at Davis. The
protocol was approved by the institutional review board
at each of the centers, and written, informed consent was
obtained from each participant before enrollment into the
study. This subgroup analysis of the original study is limited to overweight or obese individuals (BMI, $25). The
primary outcome of this study is weight change, and the
secondary outcomes are lipid levels, blood pressure, glycemic control, nutrient intake, and quality of life.
PARTICIPANTS
Adult men and women with hypertension/dyslipidemia or
with type 2 diabetes mellitus, who had been advised by their
physicians or nurses to follow special diets to manage their
conditions, were recruited through outpatient clinics and advertisements. Inclusion criteria were age 25 to 70 years, a BMI
of 42 or less, and one of the following diagnostic measures:
1. Hypertension/dyslipidemia. Untreated hypertension/
dyslipidemia were defined as an average sitting systolic blood
pressure of 140 to 180 mm Hg and/or a sitting diastolic blood
pressure of 90 to 105 mm Hg and a fasting plasma cholesterol level of 5.69 to 7.76 mmol/L (220-300 mg/dL) and/or
a fasting plasma triglyceride level of 2.26 to 11.29 mmol/L
(200-1000 mg/dL). Treated hypertension/dyslipidemia were
defined as stabilized while taking medications for 1 month
or longer before the study, a diastolic blood pressure of 100
mm Hg or lower, and a fasting cholesterol level of 6.72
mmol/L or lower (#260 mg/dL).
2. Type 2 diabetes mellitus. These persons were taking no hypoglycemic agents, had a fasting blood glucose
level of greater than 7.8 mmol/L (.140 mg/dL), and had a
glycosylated hemoglobin (HbA1c) level of 200% or less of
the median for the assay (#15.4%); or were stabilized while
taking oral hypoglycemic agents for 1 month or longer before the study, with an HbA1c level of 110% to 175% of the
median for the assay (7.7%-13.5%).
Exclusion criteria for the full study included insulin
treatment, substance abuse, and any serious health problems as noted on history or physical examination that would
interfere with study participation. For the subgroup analysis, participants with a baseline BMI of 25 or less were
excluded.
ducing cardiovascular disease risk. These include recommended daily intake levels of vitamins, minerals, and
fiber and limited intake of fats, cholesterol, and sodium.3-10 These dietary guidelines have long been recommended for the treatment of cardiovascular risk factors, including excess weight, hypertension, dyslipidemia,
and type 2 diabetes mellitus, but, to our knowledge, no
study has reported the effectiveness or safety of a diet that
simultaneously incorporates these recommendations into
A 4-week baseline period preceded the 52-week treatment
period. During this period, participants were advised to maintain their usual diets and were seen in the clinic on 3 occasions for measurements of blood pressure and weight. Two
fasting blood samples and one 4-day food record were collected. All participants were advised to maintain their usual
physical activity levels throughout the duration of the study.
Nutrition Prescriptions
For each participant, a nutrition prescription (energy intake)
was calculated during baseline using the Harris-Benedict equation16 andanactivityfactortoestimateindividualenergyneeds.
All participants were prescribed hypoenergetic nutrition prescriptions with weight loss not to exceed 0.90 kg/wk for the
intervention. The prescriptions targeted an 835.8-J range,
the lowest being 5040.0 to 5875.8 kJ/d. Participants received
their nutrition prescriptions and instructions for their use
at week 0, along with their randomization assignment.
Randomization
Individuals in each cohort were randomized separately to
the prepared meal plan or the UCD, stratified by clinic site.
Randomization was done by the study coordinating center at Oregon Health Sciences University after documentation that the subject met all the inclusion and exclusion
criteria. The randomization scheme was computer generated, with assignments by a locked computer file at the coordinating center. Randomization was done following the
participant’s second clinic visit during the baseline period, and assignments were conveyed to the respective clinic
sites by telephone and facsimile.
Treatment Period
Participants were assigned to either the prepared meal plan
or the UCD for 52 weeks. Weight and blood pressure were
measured, and blood was drawn for measurements of lipids and glucose metabolism during study visits at weeks 0,
10, 12, 24, 26, 50, and 52. All measurements were performed by study nurses unaware of the treatment assignment to maintain blinding; only the dietician at each site
was aware of the randomization group. Participants in both
groups returned completed 4-day food records at weeks 12,
26, and 52. Prepared meal plan participants received diet
adherence support at clinic visits or by telephone at
Continued on next page
a simple food plan for the management of obesityrelated cardiovascular risk factors.
The clinical benefits of the prepared meal plan have
been assessed in prior studies that demonstrated significant improvement in cardiovascular risk factors,11,12 quality of life,13 dietary compliance,14 and nutritional adequacy15 during 10-week study periods. In the present
study, we tested the effect of this meal program on weight
loss and cardiovascular risk factors in high-risk indi-
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approximately monthly intervals throughout the treatment period.
DIETARY INTERVENTIONS
The macronutrient composition of both dietary interventions targeted 22% energy from fat, 58% energy from carbohydrate, and 20% energy from protein. The prepared meal
plan comprises 7 breakfast, 13 lunch, 12 dinner, and 8 snack
selections. The meals are formulated to provide recommended levels of sodium, total and saturated fat, cholesterol, and fiber6; and are fortified to meet at least 100% of
the recommended dietary allowance for 22 essential vitamins and minerals.10 Prepared meal plan participants ordered their meal choices every 2 weeks by telephone, and
the foods were delivered to their homes.
For the prepared meal plan, participants were instructed to consume 1 breakfast, lunch, and dinner, supplemented with 1 serving each of fruit, vegetable, and low-fat
dairy products daily. They could also select 1 item per day
from a “bonus list” (in quantities equivalent to approximately 420 kJ), including vegetable oils, alcoholic beverages, or the energy equivalent in fruits, vegetables, or lowfat dairy products. If needed, prepared snacks were used
to meet prescribed energy needs.
The UCD group was prescribed a macronutrientequivalent diet based on the exchange-list system of the American Dietetic and American Diabetes Associations17; the number of servings from each exchange list was determined by
the individual’s nutrition prescription. These participants could
also select 1 serving daily from the bonus list. To balance provision of the foods to the prepared meal plan group, persons
consuming the UCD received monetary compensation for food
purchases. All participants received travel compensation in
the clinic at weeks 0, 12, 26, and 52.
OUTCOME MEASUREMENTS
Blood pressure measurements were standardized across centers by a studywide training session.18 Plasma lipoprotein
levels were determined at Northwest Lipid Research Laboratories, University of Washington, Seattle. Total cholesterol was measured by the colorimetric enzymatic end point
method (Abbott Spectrum Analyzer; Abbott Laboratories,
Abbott Park, Ill). High-density lipoprotein (HDL) cholesterol was analyzed by the heparin-manganese method.19
Low-density lipoprotein (LDL) cholesterol was calculated
using the Friedewald algorithm.20 Insulin was measured by
solid-phase radioimmunoassay (Coat-A-Count; Diagnostic Products, Los Angeles, Calif ) at the Hormone and Mineral Laboratory, Oregon Health Sciences University. The
glucose level was measured by SmithKline Beecham Clinical Laboratories, Seattle.
viduals for 52 weeks. Of the 330 persons randomized into
the study (Figure), 302 met the criterion for overweight or obesity (body mass index [BMI], $25) (BMI
is calculated as weight in kilograms divided by the square
of height in meters) and are included in the present analysis. We hypothesized that a comprehensive food program, which provided the nutrient composition, structure, portion control, and simplicity necessary to achieve
long-term weight loss, would produce significant im-
Food records were analyzed at the coordinating center with a licensed copy of the Nutrition Coordinating Center database of the University of Minnesota, St Paul (Nutrition Data System, version 2.8, 1995) supplemented by
the product content of meals provided by Campbell Soup
Company, Camden, NJ. Dietary compliance was calculated based on the percentage of energy from fat, saturated fat, and cholesterol to assess achievement of guidelines for American Heart Association Step I (,10% of energy
from saturated fat, #30% of energy from total fat, and ,300
mg/d of cholesterol) and Step II (,7% of energy from saturated fat, #30% of energy from total fat, and ,200 mg/d
of cholesterol) diets.
Quality of life was assessed using a battery of selfadministered questionnaires that measured health- and nutrition-related quality of life. The health-related instruments included the Mental Health Inventory and the General
Perceived Health, Daily Activities, Work Performance and
Satisfaction, and Sexual Function scales. Nutritionrelated measures addressed nutritional health perception,
hassles, affect, social function, and satisfaction. These instruments are described in detail elsewhere.13
STATISTICAL ANALYSIS
This study had 80% power, with a 2-sided a error level of
5%, to detect differences between treatment groups of approximately 2 mm Hg in systolic blood pressure, 0.10
mmol/L (4 mg/dL) in plasma cholesterol level, and 0.2%
difference in HbA1c level, with at least 80 persons per group.
All baseline data except weight were averaged during the
baseline period when multiple measures were available; baseline weight was that recorded at the last visit before the
intervention. The blood pressure and lipoprotein level
were averaged at weeks 10 and 12, 24 and 26, and 50 and
52, respectively. Baseline and treatment measurement data
are expressed as means ± SDs.
A repeated-measures analysis of variance model was
used to analyze differences between baseline and treatment periods for each cohort; this allowed computation of
the effect of diet between periods and of the differential
effect of the diets. An intention-to-treat approach was
used. For analysis of the proportion of participants meeting dietary compliance criteria, and the proportion of participants achieving 5% weight loss, x2 tests were used to
detect independence of categorical factors. Additional
analyses of quality-of-life data included computation of
a responsiveness index for each reported score. This
was calculated by dividing the change score between
baseline and each week by the mean within-person SD
of change between 2 measures during baseline. A score of
0.3 was a priori selected as a conservative estimate
of clinical importance.
provements in weight, multiple cardiovascular risk factors, overall nutrient intake, and quality of life.
RESULTS
BASELINE PARTICIPANT CHARACTERISTICS
The baseline characteristics of the study population are
shown in Table 1. There were no significant differ-
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ences in the distribution of age (P$.71), sex (P$.71), ethnicity (P$.16), or BMI (P$.07)between treatment or diagnostic groups.
PREPARED MEAL PLAN ADHERENCE
Adherence to the prepared meal plan was monitored by
reports at clinic visits and by the patterns of ordering the
prepared meals. Program adherence was defined as follows, and pertains to food ordering patterns between the
week 12 and the week 52 visits: full program adherence,
21 meals per week; partial adherence, averaged to less
than 21 meals per week; and off the program, did not order any prepared meals. The ordering patterns of participants with hypertension/dyslipidemia and of those with
type 2 diabetes mellitus were as follows at week 26: full
program, 49% and 53%; partial program, 45% and 44%;
and off the program, 6% and 2%, respectively. At week
52, these respective proportions were as follows: full program, 33% and 39%; partial program, 56% and 38%; and
off the program, 11% and 29%.
Eligible Patients
(n=780)
Met Enrollment Criteria
(n=330)
Randomization
Hypertension/Dyslipidemia (n=196)
Type 2 Diabetes Mellitus (n=134)
Prepared Meal Plan
Usual-Care Diet
Hypertension/Dyslipidemia (n=93)
Type 2 Diabetes Mellitus (n=56)
Week 0
Hypertension/Dyslipidemia (n=90)
Type 2 Diabetes Mellitus (n=63)
Hypertension/Dyslipidemia (n=90)
Type 2 Diabetes Mellitus (n=54)
Week 12
Hypertension/Dyslipidemia (n=85)
Type 2 Diabetes Mellitus (n=56)
Hypertension/Dyslipidemia (n=86)
Type 2 Diabetes Mellitus (n=43)
Week 26
Hypertension/Dyslipidemia (n=82)
Type 2 Diabetes Mellitus (n=51)
Hypertension/Dyslipidemia (n=79)
Type 2 Diabetes Mellitus (n=41)
Week 52
Hypertension/Dyslipidemia (n=79)
Type 2 Diabetes Mellitus (n=51)
Withdrew
Hypertension/Dyslipidemia (n=18)
Type 2 Diabetes Mellitus (n=15)
n=10
n=3
n=0
n=5
n=9
n=1
n=1
n=4
Diet-related adverse effects in the prepared meal plan vs
the UCD group were reported by 10% vs 1% of participants with hypertension/dyslipidemia (P,.05) and 6%
vs 2% of participants with type 2 diabetes mellitus. Three
symptoms accounted for these differences: flatulence, 2%
vs 0% for hypertension/dyslipidemia and 3% vs 0% for
diabetes; abdominal pain, 3% vs 0% for hypertension/
dyslipidemia and none for type 2 diabetes mellitus; and
diarrhea, 3% vs 0% for hypertension/dyslipidemia and
none for type 2 diabetes mellitus. With few exceptions,
symptoms were reported at only 1 visit, were selflimiting, and thus did not affect program adherence.
Withdrew
Hypertension/Dyslipidemia (n=11)
Type 2 Diabetes Mellitus (n=12)
Hypertension/
Type 2
Dyslipidemia
Diabetes
Group
Mellitus Group
Unavailable for Follow-up
Did Not Like Meals
Medical
Other
ADVERSE EFFECTS
Hypertension/
Type 2
Dyslipidemia
Diabetes
Group
Mellitus Group
Unavailable for Follow-up
Did Not Like Meals
Medical
Other
n=9
n=1
n=1
n=0
n=10
n=0
n=0
n=2
Participants qualifying for the study with hypertension and dyslipidemia or
with type 2 diabetes mellitus were randomized to either the prepared meal
plan or the usual-care diet. The study schema is shown for assessment of
body weight and secondary outcomes. Participants with a body mass index
(calculated as weight in kilograms divided by the square of height in meters)
less than 25 were excluded from this subgroup analysis (n=11 in the
hypertension/dyslipidemia group and n=13 in the diabetes mellitus group).
Of the 183 randomized participants with hypertension/dyslipidemia and the
119 with type 2 diabetes mellitus who qualified as being overweight or
obese, 56 did not complete a week 52 visit. The most frequent reason given
for early withdrawal from the study was the excessive time commitment
required to complete the study.
OUTCOME MEASURES
Hypertension/Dyslipidemia Group
Weight Loss. Participants consuming the prepared meal
plan lost significantly more weight than those consuming the UCD during the 52-week study period (P,.001).
Table 1. Baseline Characteristics of Study Participants*
Participants With
Type 2 Diabetes Mellitus
Participants With
Hypertension/Dyslipidemia
Characteristics
Age, mean ± SD, y
Sex
Male
Female
Race
White
African American
Other
BMI, mean ± SD†
Overweight, No. (%)‡
Obese, No. (%)§
Prepared Meal Plan
(n = 93)
Usual-Care Diet
(n = 90)
Prepared Meal Plan
(n = 56)
Usual-Care Diet
(n = 63)
54.5 ± 9.0
54.4 ± 9.5
54.6 ± 9.0
54.0 ± 9.9
43
50
86
5
2
33.0 ± 4.9
30 (32)
63 (68)
40
50
77
7
6
32.0 ± 4.2
32 (36)
58 (64)
25
31
47
4
5
33.0 ± 4.4
17 (30)
39 (70)
*Data are given as the number of participants unless otherwise indicated.
†BMI indicates body mass index (calculated as weight in kilograms divided by the square of height in meters).
‡Defined as a BMI between 25.0 and 29.9.
§Defined as a BMI of 30 or greater.
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25
38
48
9
6
34.5 ± 4.5
12 (19)
51 (81)
Table 2. Diet Effects on Outcome Measures*
Prepared Meal Plan
Outcome Measure
Baseline
12-wk Change
26-wk Change
52-wk Change
SBP, mm Hg†
DBP, mm Hg
Cholesterol, mmol/L (mg/dL)†
Triglycerides, mmol/L (mg/dL)
HDL cholesterol, mmol/L (mg/dL)†
LDL cholesterol, mmol/L (mg/dL)
Glucose, mmol/L (mg/dL)†
Insulin, pmol/L
HbA1c, %‡
Participants With Hypertension/Dyslipidemia
(n = 93)
(n = 90)
(n = 86)
(n = 79)
145.0 ± 10
12.2 ± 10.6
−12.9 ± 10.2
−11.9 ± 11.7
91.4 ± 5.3
−7.5 ± 5.8
−7.4 ± 6.7
−7.0 ± 6.6
6.03 ± 0.74 (233.0 ± 28.0) −0.48 ± 0.67 (−18.5 ± 25.9) −0.10 ± 0.70 (−4.0 ± 27.1)
−0.16 ± 0.77 (−6.3 ± 29.9)
2.53 ± 1.50 (224.0 ± 133.0) −0.30 ± 1.26 (−26.5 ± 112.0) −0.21 ± 1.34 (−18.7 ± 119.0) −0.24 ± 1.13 (−21.3 ± 99.8)
1.22 ± 0.38 (47.0 ± 14.5)
−0.06 ± 0.15 (−2.2 ± 5.8)
0.04 ± 0.15 (1.7 ± 6.0)
0.06 ± 0.17 (2.1 ± 6.5)
3.68 ± 0.80 (142.0 ± 31.0) −0.29 ± 0.58 (−11.1 ± 22.5) −0.02 ± 0.64 (−0.7 ± 24.8)
−0.11 ± 0.70 (−4.2 ± 27.1)
5.1 ± 0.9 (92.8 ± 16.6)
−0.2 ± 0.8 (−2.9 ± 13.6)
−0.1 ± 1.0 (−2.6 ± 17.9)
−0.2 ± 0.9 (−4.3 ± 15.4)
21.9 ± 12.6
−6.0 ± 10.4
−6.8 ± 10.2
−5.5 ± 11.1
5.65 ± 0.42
−0.01 ± 0.30
0.05 ± 0.33
0.05 ± 0.33
SBP, mm Hg
DBP, mm Hg
Cholesterol, mmol/L (mg/dL)†
Triglycerides, mmol/L (mg/dL)
HDL cholesterol, mmol/L (mg/dL)
LDL cholesterol, mmol/L (mg/dL)
Glucose, mmol/L (mg/dL)†
Insulin, pmol/L
HbA1c, %†‡
(n = 56)
137.0 ± 15.3
82.4 ± 6.7
5.38 ± 1.0 (208.0 ± 39.0)
2.88 ± 1.87 (255.0 ± 166.0)
1.04 ± 0.25 (40.2 ± 9.6)
3.14 ± 0.98 (121.0 ± 38.0)
10.5 ± 2.8 (189.0 ± 49.7)
28.5 ± 15.5
8.76 ± 1.43
(n = 54)
−8.5 ± 9.4
−3.7 ± 5.7
−0.28 ± 0.62 (−10.7 ± 23.9)
−0.44 ± 0.99 (−39.0 ± 87.4)
−0.02 ± 0.12 (−0.9 ± 4.6)
−0.12 ± 0.57 (−4.8 ± 22.1)
−2.1 ± 2.6 (−38.7 ± 47.0)
−8.5 ± 12.5
−1.04 ± 1.03
Participants With Type 2 Diabetes Mellitus
(n = 43)
(n = 41)
−7.0 ± 11.2
−8.8 ± 12.6
−5.1 ± 6.3
−5.1 ± 5.6
0.39 ± 0.40 (3.2 ± 30.0)
0.16 ± 0.76 (6.2 ± 29.2)
−0.40 ± 1.15 (−35.7 ± 102.0) −0.16 ± 1.41 (−14.2 ± 126.0)
0.07 ± 0.11 (2.6 ± 4.2)
0.05 ± 0.15 (1.9 ± 5.7)
0.16 ± 0.72 (6.2 ± 27.9)
0.18 ± 0.69 (7.0 ± 26.7)
−1.7 ± 3.0 (−30.9 ± 54.7)
−0.6 ± 3.3 (−11.2 ± 59.8)
−4.5 ± 17.4
−4.9 ± 11.9
−0.87 ± 1.29
−0.24 ± 1.52
*Data are given as mean ± SD. SBP indicates systolic blood pressure; DBP, diastolic blood pressure; HDL, high-density lipoprotein; LDL, low-density
lipoprotein; and HbA1c, glycosylated hemoglobin.
†P,.05 for the difference between diets over time.
‡Measured as a percentage of total hemoglobin.
In the prepared meal plan group, the average weight loss
from baseline was 6.9±4.0 kg after 12 weeks, 7.8±6.3 kg
after 26 weeks, and 5.8±6.8 kg after 52 weeks of treatment; they maintained 74% of their week 26 weight loss
by the end of the study. The UCD group lost 2.3±3.6 kg
after 12 weeks, 2.4±5.4 kg after 26 weeks, and 1.7±6.5 kg
after 52 weeks of treatment; they maintained 71% of their
week 26 weight loss. Weight loss of at least 5% was achieved
by 45 (57%) of 79 prepared meal plan participants compared with 15 (19%) of 79 UCD participants (P,.001).
Blood Pressure. The prepared meal plan group had significantly greater reductions in systolic blood pressure
during the study period than the UCD group (P,.03);
no significant (P=.21) difference between groups was observed for diastolic blood pressure (Table 2). Week 52
blood pressure changes from baseline were significantly
reduced in both diet groups (P,.001).
Lipids and Lipoproteins. Changes in total (P,.01) and
HDL (P,.03) cholesterol levels during 52 weeks were
significantly different in the prepared meal plan group
compared with the UCD group; no significant differences were observed between diets for LDL cholesterol
(P=.14) or triglyceride (P=.54) levels. Week 52 changes
in total, LDL, and HDL cholesterol levels from baseline
were significantly different in both diet groups (P,.001).
Indexes of Glycemic Control. Participants consuming
the prepared meal plan had significantly greater reductions in glucose level during the study period than those
consuming the UCD (P,.03) (Table 2). No significant
differences were observed between diet groups for insulin (P=.07) and HbA1c (P =.11) levels. Week 52 changes
in insulin and HbA1c levels from baseline were significantly reduced in both diet groups (P,.001).
Reported Nutrient Intake. Reported intake of selected macronutrients at baseline and week 52 is shown in Table 3.
Participants in the prepared meal plan group had greater
increases during the study period in carbohydrate intake
and greater reductions in intakes of cholesterol and percentage of energy from total fat compared with UCD participants (P,.001). Changes in reported intakes of energy and percentage of energy from protein did not differ
between diet groups during the study period. Reported intakes of all nutrients changed from baseline during the study
period in both diet groups (P,.01).
Dietary Compliance. Throughout the intervention period, the prepared meal plan group reported greater compliance with American Heart Association Step I and Step
II dietary recommendations compared with the UCD
group (P,.001). At baseline, 29% of both dietary groups
reported compliance with Step I recommendations; 5%
of the prepared meal plan group and 12% of the UCD
group met Step II guidelines. Compliance with Step I recommendations across the weeks of study was achieved
by the following proportions of the prepared meal plan
group compared with the UCD group: 92% vs 44% at week
12, 75% vs 37% at week 26, and 74% vs 37% at week 52.
The proportions compliant with Step II guidelines were
as follows: 72% vs 19% at week 12, 56% vs 19% at week
26, and 43% vs 17% at week 52.
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Usual-Care Diet
Baseline
12-wk Change
26-wk Change
(n = 90)
145.0 ± 10.8
90.3 ± 5.6
6.05 ± 0.75 (234.0 ± 29.0)
2.50 ± 1.29 (222.0 ± 114.0)
1.17 ± 0.30 (45.3 ± 11.6)
3.75 ± 0.87 (145.0 ± 34.0)
5.1 ± 1.0 (92.2 ± 17.9)
21.7 ± 18.1
5.63 ± 0.46
(n = 85)
−9.2 ± 9.6
−5.9 ± 6.4
−0.21 ± 0.56 (−7.9 ± 21.7)
0.00 ± 0.96 (−0.1 ± 85.5)
−0.05 ± 0.12 (−1.8 ± 4.5)
−0.16 ± 0.48 (−6.3 ± 18.4)
0.1 ± 0.8 (1.8 ± 14.3)
−2.0 ± 12.3
0.03 ± 0.31
(n = 82)
−9.0 ± 11.0
−6.8 ± 6.5
−0.19 ± 0.69 (−7.2 ± 26.8)
−0.02 ± 1.64 (−1.9 ± 145.0)
0.01 ± 0.10 (0.5 ± 3.8)
−0.16 ± 0.57 (−6.3 ± 22.0)
0.2 ± 0.9 (2.8 ± 16.9)
−3.2 ± 12.6
0.13 ± 0.31
{n = 79)
−10.5 ± 13.2
−6.5 ± 6.8
−0.22 ± 0.66 (−8.5 ± 25.6)
−0.10 ± 1.05 (−8.9 ± 92.8)
0.00 ± 0.13 (0.1 ± 5.0)
−0.17 ± 0.58 (−6.7 ± 22.6)
0.0 ± 9.0 (0.8 ± 16.1)
−2.8 ± 15.5
0.16 ± 0.31
(n = 63)
138.0 ± 12.8
83.7 ± 8.3
5.28 ± 0.87 (204.0 ± 34.0)
2.63 ± 1.65 (233.0 ± 146.0)
1.04 ± 0.27 (40.3 ± 10.4)
3.11 ± 0.90 (120.0 ± 35.0)
11.1 ± 2.6 (199.4 ± 47.2)
28.0 ± 18.2
8.82 ± 1.24
(n = 56)
−5.7 ± 8.0
−2.7 ± 4.4
−0.06 ± 0.46 (−2.3 ± 17.9)
−0.13 ± 1.10 (−11.5 ± 97.8)
−0.02 ± 0.09 (−0.8 ± 3.6)
0.01 ± 0.41 (0.4 ± 16.0)
−0.6 ± 2.3 (−10.7 ± 42.0)
−3.1 ± 11.1
−0.31 ± 1.07
(n = 51)
−6.0 ± 10.7
−3.0 ± 5.0
0.70 ± 0.53 (0.9 ± 26.1)
−0.10 ± 1.79 (−8.8 ± 159.0)
0.01 ± 0.12 (0.5 ± 4.5)
0.06 ± 0.44 (2.2 ± 17.2)
−0.5 ± 2.7 (−8.2 ± 49.5)
−1.8 ± 10.5
−0.22 ± 1.30
(n = 51)
−9.9 ± 13.2
−3.8 ± 6.2
0.03 ± 1.08 (1.0 ± 41.7)
0.06 ± 3.09 (5.1 ± 274.0)
0.01 ± 0.13 (0.3 ± 5.2)
−0.01 ± 0.64 (−0.3 ± 24.6)
−0.6 ± 3.4 (−10.9 ± 61.6)
−2.5 ± 12.6
−0.20 ± 1.30
Quality of Life. During the intervention period, participants in the prepared meal plan group reported significantly greater improvements in quality of life compared
with UCD participants on the following scales: Mental
Health Inventory (P,.01), General Health Perceptions
(P,.001), Daily Activities (P,.001), Work Performance (P,.02), Nutritional Hassles (P,.001), Nutritional Health Perceptions (P,.001), Nutrition and Social Function (P,.045), Nutrition and Affect (P,.001),
and Satisfaction With Diet (P,.001).
Type 2 Diabetes Mellitus Group
Weight Loss. Participants consuming the prepared meal
plan lost significantly more weight than participants consuming the UCD (P,.001). In the prepared meal plan
group, the average weight loss from baseline was 4.7±4.0
kg after 12 weeks, 5.5±6.4 kg after 26 weeks, and 3.0±5.4
kg after 52 weeks of treatment; these participants maintained 55% of their week 26 weight loss by the end of
the study. The UCD group lost 1.3±2.5 kg after 12 weeks,
1.5±3.2 kg after 26 weeks, and 1.0±3.8 kg after 52 weeks
of treatment; this group maintained 67% of their week
26 weight loss by the end of the study. Weight loss of at
least 5% was achieved by 12 (29%) of 41 prepared meal
plan participants compared with 5 (10%) of 51 UCD participants (P,.03).
Blood Pressure. Changes in systolic or diastolic blood
pressure were not significantly different in participants
consuming the prepared meal plan compared with the
UCD (Table 2). Week 52 blood pressure changes from
52-wk Change
baseline were significantly reduced in both diet groups
(P,.001).
Lipids and Lipoproteins. The change in total (P,.03)
and LDL (P,.01) cholesterol levels between diet groups
during the 52-week trial was significantly different in the
prepared meal plan compared with the UCD group; no
significant differences were observed between diets in HDL
cholesterol or triglyceride levels (Table 2). Despite a decrease in total cholesterol level after 12 weeks with the
prepared meal plan, the cholesterol level increased during the remainder of the trial; in the UCD group, the cholesterol level did not change markedly from baseline. Week
52 changes in total, LDL, and HDL cholesterol levels from
baseline were significantly different in both diet groups
(P,.02).
Indexes of Glycemic Control. Participants consuming
the prepared meal plan had significantly greater reductions in glucose (P=.046) and HbA1c (P,.02) levels during the study period than those consuming the UCD. No
differences were observed between diet groups in insulin level (Table 2). Week 52 changes in glucose, insulin,
and HbA1c levels from baseline were significantly different in both diet groups (P,.001).
Reported Nutrient Intake. Reported intake of selected
macronutrients at baseline and week 52 is shown in Table
3. Participants in the prepared meal plan group had greater
increases during the study period in carbohydrate intake and greater reductions in intakes of cholesterol and
percentage energy from total fat compared with UCD par-
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Table 3. Changes in Reported Macronutrient Intake in Study Participants Consuming the Prepared Meal Plan
and the Usual-Care Diet*
Usual-Care Diet
Prepared Meal Plan
Macronutrient Intake
Baseline
Energy, kJ/d (kcal/d)
Energy from protein, %
Energy from carbohydrate, %†
Energy from fat, %†
Energy from saturated fat, %†
Cholesterol, mg†
Energy, kJ/d (kcal/d)
Energy from protein, %
Energy from carbohydrate, %†
Energy from fat, %†
Energy from saturated fat, %†
Cholesterol, mg†
Week 52
Change
Baseline
Week 52
Change
(n = 98)
9011 ± 2832
(2154 ± 677)
16.5 ± 3.4
50.6 ± 8.3
32.7 ± 7.1
11.0 ± 2.8
285 ± 148
Participants With Hypertension/Dyslipidemia
(n = 72)
(n = 72)
(n = 90)
6703 ± 1909
−2301 ± 2850
9263 ± 2590
(1602 ± 456)
(−550 ± 681)
(2214 ± 619)
18.4 ± 3.0
1.7 ± 3.9
15.8 ± 3.3
58.4 ± 7.5
8.0 ± 8.3
51.5 ± 8.1
23.3 ± 6.5
−9.6 ± 8.1
32.6 ± 6.9
7.9 ± 2.6
−3.2 ± 3.0
10.8 ± 3.2
150 ± 94
−135 ± 147
271 ± 123
(n = 78)
7500 ± 2307
(1793 ± 551)
17.3 ± 3.2
52.9 ± 8.9
29.9 ± 7.4
9.9 ± 3.3
235 ± 154
(n = 78)
−1926 ± 2109
(−460 ± 504)
1.7 ± 3.7
1.1 ± 7.7
−2.7 ± 6.9
−0.9 ± 2.8
−36 ± 154
(n = 56)
8920 ± 3020
(2132 ± 722)
17.5 ± 4.0
48.5 ± 8.2
35.2 ± 7.2
11.8 ± 2.9
306 ± 155
Participants With Type 2 Diabetes Mellitus
(n = 39)
(n = 39)
(n = 63)
6415 ± 2026
−2180 ± 2357
9198 ± 2585
(1533 ± 484)
(−521 ± 563)
(2198 ± 618)
19.3 ± 3.4
1.3 ± 3.4
17.0 ± 3.5
54.0 ± 9.1
5.9 ± 10.2
47.9 ± 7.1
27.6 ± 8.6
−7.4 ± 9.0
35.4 ± 6.5
9.0 ± 2.8
−2.6 ± 3.5
11.4 ± 2.6
181 ± 124
−114 ± 179
318 ± 120
(n = 47)
7797 ± 4263
(1863 ± 1019)
18.4 ± 4.3
49.8 ± 9.7
32.3 ± 8.5
10.6 ± 3.6
269 ± 230
(n = 47)
−1367 ± 3611
(−327 ± 863)
1.2 ± 3.7
1.6 ± 10.0
−2.8 ± 8.3
−0.6 ± 3.5
−30 ± 231
*Data are given as mean ± SD.
†P,.001 for the difference in the nutrient change over time between diets.
ticipants (P,.001). Changes in reported intakes of energy and percentage energy from protein did not differ
between diet groups during the study period. Reported
intakes of all nutrients changed from baseline during the
study period in both diet groups (P,.01).
Dietary Compliance. At weeks 12 and 26, the prepared
meal plan group was more compliant with American Heart
Association Step I and Step II dietary recommendations
compared with the UCD group (P,.001). At baseline,
16% of the prepared meal plan group and 11% of the UCD
group were compliant with Step I recommendations; 4%
of the prepared meal plan group and 5% of the UCD group
met Step II guidelines. Compliance with Step I recommendations across the weeks of study was achieved by
the following proportions of the prepared meal plan group
compared with the UCD group: 87% vs 31% at week 12,
68% vs 33% at week 26, and 56% vs 36% at week 52. The
proportions compliant with Step II guidelines were as follows: 64% vs 12% at week 12, 39% vs 11% at week 26,
and 31% vs 15% at week 52.
Quality of Life. During the intervention period, participants in the prepared meal plan group reported significantly greater improvements in quality of life compared
with UCD participants on the following scales: Mental
Health Inventory (P,.04), Daily Activities (P,.03), Nutritional Hassles (P,.01), Nutritional Health Perceptions (P,.001), Nutrition and Affect (P,.01), and Satisfaction With Diet (P,.001).
COMMENT
To our knowledge, this is the first year-long randomized trial in persons with established risk factors for cardiovascular disease to test the effect on weight loss of a
prepared meal plan meeting all of the nutrient recommendations of national health organizations.3-10 The results demonstrate that the prepared meal plan is more
effective in inducing weight loss in such subjects than a
macronutrient-equivalent UCD. Accordingly, the prepared meal plan was more effective in improving multiple risk factors while simultaneously enhancing the participants’ quality of life.
After 6 months of consuming the prepared meal plan,
weight reduction was 8% and 6% of baseline in participants with hypertension/dyslipidemia and in those with
type 2 diabetes mellitus, respectively, compared with 2%
for both diagnostic groups in participants receiving the
UCD. At 1 year, weight loss had regressed to 6% and 3%
of baseline in participants with hypertension/
dyslipidemia and in those with type 2 diabetes mellitus,
respectively, while consuming the prepared meal plan.
However, among participants compliant with Step I recommendations, weight loss had improved to 7% and 5%
of baseline levels, respectively.
Short-term weight reductions of 5% to 15% have been
reported to significantly improve obesity-related comorbidities.21,22 The weight loss we observed among prepared meal plan participants is consistent with those prior
reports and other nonpharmacological weight loss interventions.2 The greater weight loss in the prepared meal
plan group likely reflects, in part, better dietary compliance and, thus, greater sustained reductions in energy
and fat intake.
Blood pressure, plasma lipid and lipoprotein levels, and glycemic control indexes improved significantly in both intervention groups. Weight changes as
small as 2% of baseline were associated with modest
but significant improvements in total, LDL, and HDL
cholesterol (hypertension/dyslipidemia group only);
glucose (diabetic group only); insulin; and HbA1c lev-
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els. The prepared meal plan was associated with a
more favorable risk factor profile, including systolic
blood pressure (hypertension/dyslipidemia group
only) and HDL cholesterol, glucose, and HbA1c (diabetic group only) levels.
The response in total and LDL cholesterol with the
prepared meal plan compared with usual care may be due
in part to the participants’ modestly elevated baseline lipid
levels. Higher baseline lipid levels are more responsive
to lipid-lowering interventions.23-25 In our study, baseline levels were only borderline high in the hypertension/
dyslipidemia group and normal in the diabetic group.
Similarly, baseline dietary fat intake was not excessively
high, possibly attenuating greater lipid responses with
the intervention. Mean fat intakes averaged 32% energy
from fat in the hypertension/dyslipidemia group and 35%
in the diabetic group, approaching the American Heart
Association recommendation of 30%. Improvements in
HDL cholesterol level were greater among the participants with hypertension/dyslipidemia consuming the prepared meal plan (P,.03) and nearly so in participants
with type 2 diabetes (P,.06). This finding is consistent
with other reports23,26,27 of weight loss–associated increases in HDL cholesterol level and is essential to improving cardiovascular risk.
Prior concerns that substantial reductions in dietary fat and reciprocal increases in carbohydrate intake
would exacerbate plasma triglyceride levels and indexes of glycemic control, particularly in participants with
type 2 diabetes, were not observed, likely as a result of
weight loss. To the contrary, triglyceride levels initially
decreased in participants with type 2 diabetes mellitus
consuming the prepared meal plan, with a commensurate reported fat intake of 24% at week 26. By week 52,
triglyceride levels were essentially unchanged among the
dietary groups. More important, during the year, plasma
glucose and HbA1c levels significantly improved in participants with type 2 diabetes consuming the prepared
meal plan compared with those consuming the UCD.
The enhanced quality of life reported with the prepared meal plan may be essential to the success of this
program. Improved clinical outcomes are not necessarily sufficient motivation to assure long-term patient
acceptance of dietary changes. Results from numerous
interventions intended to modify chronic disease risk
have shown that patients must perceive themselves as
better off or the intervention will not be sustained.
Improved quality of life has been shown previously to
be positively related to weight loss.28-31 The enhanced
quality-of-life scores in the prepared meal plan group
reflect not only the weight loss but also concurrent
reductions in cardiovascular disease risk factors,32 perceived beneficial changes in dietary practices, positive
effect associated with personal control of disease management,33 and the simplicity of achieving these multiple benefits. Thus, our observation that quality of life
improved may be critical to assuring longer adherence
to this dietary intervention.
Our findings support the therapeutic concept that
modest and substantial weight loss through dietary means
improves cardiovascular disease risk factors. In addition, we have documented the safety, efficacy, and ac-
ceptability of a prepared meal program in this year-long
randomized trial. While other dietary and pharmacological approaches may offer similar benefits, documentation through a 12-month intervention period awaits critical testing.
These findings validate the hypothesis of a positive
impact of long-term dietary interventions on weight loss
and cardiovascular risk reduction in high-risk patients.
The prepared meal plan promoted and sustained longterm weight loss and reduced cardiovascular risk. The
simplicity, variety, portion control, and nutrient composition necessary to enhance and maintain long-term
dietary compliance while concomitantly improving quality of life were critical to achieving these outcomes.
Accepted for publication January 28, 2000.
From the Division of Nephrology, Hypertension, and
Clinical Pharmacology, Department of Medicine, Oregon
Health Sciences University (Drs Metz, Morris, Hatton, and
McCarron, Ms Reusser, and Mr Snyder), and the Clinical
Research Group of Oregon (Dr Clark and Mss Chester and
McMahon), Portland; and Division of Clinical Nutrition and
Metabolism, Departments of Nutrition and Internal Medicine, University of California at Davis (Dr Stern); the Nutrition Department, College of Health and Human development, Pennsylvania State University, University Park (Dr
Oparil); the Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario (Dr
Haynes); the Division of Endocrinology/Hypertension, Wayne
State University Medical Center, Detroit, Mich (Dr Resnick);
and the Division of Endocrinology, Diabetes, and Nutrition, St Luke’s/Roosevelt Hospital, Columbia University, New
York, NY (Dr Pi-Sunyer).
This study was supported by the Campbell’s Center
for Nutrition & Wellness, Campbell Soup Company,
Camden, NJ.
Reprints: Jill A. Metz, PhD, Division of Nephrology,
Hypertension, and Clinical Pharmacology, Suite 262,
Oregon Health Sciences University, 3314 SW Veterans
Hospital Rd, Portland, OR 97201-2940 (e-mail: metzj
@ohsu.edu).
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