- Click here for explanation of classification scheme.

The purpose of this study is to compare the dietary compliance and CVD risk factor response in two dietary interventions designed to treat hypertension, dyslipidemia, and diabetes mellitus.

1. 25 to 70 years of age
2. Body Mass Index up to 42
3. One or more of the following criteria:
   • Hypertension: Taking no anti-hypertensive medications and average systolic BP 140mm to 180mm hg, sitting diastolic BP 90mm to 105mm Hg, or both or stabilized through use of anti-hypertensive medications for at least one month before the study and average sitting systolic BP of 135-180mm Hg or diastolic BP 85mm to 100mm Hg
   • Dyslipidemia: Taking no lipid-lowering medications and total cholesterol concentration of 220mg 300mg per dL, triacyglycerol concentration of 200mg 1,000mg per dL, or both or stabilized through use of lipid-lowering medications for at least one month before study and a cholesterol concentration of 200mg to 260mg per dL, triacylglycerol contration of 200mg to 1,000mg per dL or both
   • NIDDM: Taking no hypoglycemic agents, fasting blood glucose concentration over 140mg per dL and glycated hemoglobin (HbA1c) concentration up to 15.4% or stabilized through use of oral hypoglycemic agents for at least one month before study with HbA1c concentrations 7.7% to 13.4%
   • A combination of disorders: Meet the criteria for more than one of the above categories.

1. Does not meet the above inclusion criteria
2. Life-threatening diseases
3. Receiving insulin treatment
4. Pregnant or not practicing birth control
5. Substance or alcohol abuse
6. Refusal to discontinue vitamin-mineral supplements.

Recruitment

Subjects were recruited at 10 different clinical centers around the United States.

Design

• All subjects were initially enrolled in a baseline period (Weeks Four through Zero) and advised to maintain their usual diets and seen weekly for blood pressure and weight measurements. They were instructed on completing three-day food records and two of these were collected during this period. A physical exam was conducted and fasting blood was collected to measure chemistry profile, HbA1c and lipid and lipoproteins. Participants were asked to maintain their usual physical activity levels.
• At Week Two, a nutrition prescription was calculated for each patient using Harris-Benedict equation. Calculations were made with the goal of limiting weight loss to one kg per week and a total of 11kg for the intervention.
• At Week Two, subjects were randomly assigned by the coordinating center to either the prepared meal plan or self-selected diet group; stratified by four diagnostic categories (hypertension, dyslipidemia, NIDDM or combination of above) and clinic site.
• Subjects consumed either the prepared meal plan or the self-selected meals for 10 weeks. They were seen every two weeks for measurements of BP, weight and collection of three-day food record. Fasting blood was collected at weeks zero and 10 for the measurements described above, at week four for glucose and lipoproteins and again at week eight for lipoproteins.

Intervention

• At Week Zero, all participants were counseled regarding their assigned therapeutic diet and were provided with educational materials to help them adhere to their program for the 10-week intervention.
• The prepared meals were produced by the Campbell Soup Company and included six breakfast, eight lunch, 10 dinner and six snack selections. Meals were ordered by participants at clinic visits and the foods were delivered to their homes. Participants were instructed to consume one serving each day of the breakfast, lunch, and dinner entrées and to include one serving daily of fruit, vegetables and low-fat dairy products.
• Participants in the self-selected diet group were prescribed a specific number of servings from each of the ADA exchange lists that were congruent with providing 15-20% of energy from fat, 55-60% from carbohydrate and 15-20% from protein. The self-selected diet closely resembled the National Cholesterol Education Program and American Heart Association Step 2 Diet.

Statistical Analysis

• The study was designed to detect differences between treatment groups of three mm Hg in BP, 10mg per dL in plasma cholesterol, 20mg per dL in triacylglycerols, 10mg per dL in plasma glucose and a 1% difference in HbA1c. With a power of ≥ 80% and a two-sided alpha of 0.05, these differences were detectable with a sample of 80 in each group based on variation as defined in a preliminary study. 
• A repeated measures analysis of variance model was used to analyze differences between baseline and treatment periods.
• Changes in nutrient intake from baseline to treatment were analyzed by using analysis of repeated measures.
• For analysis of the proportion of participants meeting dietary compliance criteria, and the compliance-end-point responses, chi-square tests were used to detect independence of categorical factors.

 

Timing of Measurements

Subjects were seen every two weeks for measurements of BP, weight and collection of three-day food record. Fasting blood was collected at weeks zero and 10 for the measurements described above, at week four for glucose and lipoproteins and again at week eight for lipoproteins. Three-day food records were collected at weeks two, four, six, eight and 10.

Dependent Variables

Variable One: Dietary Compliance, assessed from three-day food records by evaluating the ability of participants to meet specific dietary criteria for intakes of energy from total fat and the NCEP/AHA Step 1 and 2 dietary recommendations. Baseline nutrient intakes were estimated by averaging nutrient intake from two three-day food records collected over the course of the study.

• 1a: Energy (kcal): Determined by calculating the difference between reported energy intake and the midpoint of the prescribed energy range
• 1b: Protein (g)
• 1c: Carbohydrate (g)
• 1d: Total Fat (g): The fat composition of both diets averaged 17% and this was used as an index of compliance.
• 1e: Energy from fat (percentage)
• 1f: Energy from protein (5)
• 1g: Energy from carbohydrate (percentage)
• 1h: Energy from SFA (percentage)
• 1j: Energy from PUFA (percentage)
• 1k: PUFA (g)
• 1l: Energy from MUFA (percentage)
• 1m: MUFA (g)
• 1n: Cholesterol (mg)
• 1o: Calcium (mg)
• 1p: Fiber (g)
• 1q: Potassium (mg)
• 1r: Sodium (mg)
• 1s: Magnesium (mg)
• 1t: Folate (microgm).

Variable Two: Changes in study endpoints

• 2a: Sitting systolic BP (mm Hg): Determined in accordance with recommendations of the AHA
• 2b: Sitting diastolic BP (mmg Hg)
• 2c: Cholesterol (mmol/L): Plasma lipoproteins determined at the Northwest Lipid Laboratories, University of Washington. T-Chol measured by the colorimetric enzymatic endpoint method
• 2d: Triaclyglycerol (mmol/L)
• 2e: LDL (mmol per L): Calculated by using the Friedewald algorithm
• 2f: HDL (mmol per L): Analyzed by the heparin-manganese method
• 2g: VLDL (mmol per L)
• 2h: Insulin (pmol per L): Measured by using a solid phase radio-immunoassay at the Hormone and Mineral laboratory, Oregon Health Sciences University
• 2i: Weight (kg)

Independent Variables

1. Prepared meal plan
2. Self-selected diet.

 Control Variables

1. Three-day food records with instruction for completion
2. Nutrition prescription calculated using Harris-Benedict Equation to estimate individual energy needs
3. Educational material and verbal instruction on following prescribed diet plans. Dietary counseling provided to all subjects by study nutritionists.

Initial N

• 560
• Prepared meal plan: 283
• Self-selected diet: 277.

Attrition (Final N)

• Prepared Meal Plan Group: N=272 (92%)
• Self-Selected Diet Group: N=270 (97%).

Demographics

Demographics		Prepared Meal Plan N=114	Prepared Meal Plan Women N=169	Self Selected Diet Men N=132	Self-Selected Diet Women N=145
Age (years)		55±10	54±10	53±9	54±9
Race (percentage)	White	84	85	86	83
	African-American	13	9	8	11
	Other	3	6	6	6
BMI (kg/m2)		31±4	31±5	31±4	31±5
Current Smokers (percentage)		16	9	12	10
Alcohol Intake (percentage)		56	48	62	54
Education (years)		15.0±3.0	14.2±2.7	14.9±3.0	13.8±2.5

Other Significant Demographics

In the dyslipidemia group, there were more African-American and Hispanic participants in the self-selected diet group.

Changes in reported daily nutrient intakes in study participants stratified by sex and treatment group from baseline to end of treatment.¹

Women                    

Variables	Prepared Meal Plan Baseline (N=169 W, 114 M)	Prepared Meal Plan Treatment (N=163 W, 109 M)	Prepared Meal Plan Change N=163 W, 109 M)	Self-Selected Diet         Baseline (N=145 W, 132 M)	Self-Selected Diet  Treatment (N=142 W, 128 M)	Self-Selected Diet Change (N=142 W, 128 M)
Energy (kcal)	1,772±460	1,436±288	-327	1,768±494	1,386±323	-387
Protein (grams)	74±18	72±11	-13	72±19	67±15	-6
Carbohydrate (grams)	227±65	217±43	-10	217±65	201±51	-17
Total Fat (grams)	65±25	29±11	-35	69±27	37±15	-31
Energy from fat (percentage)	32±7	18±3	-143	34±6	24±6	-10
Energy from Protein (percentage)	17±3	20±2	3	17±3	20±3	3
Energy from Carbohydrate (percentage)	52±8	61±4	9	49±7	58±6	9
Energy from SFA (percentage)	10.9±3.0	6.2±1.3	-4.73	11.4±2.8	7.5±2.1	-3.8
Saturated Fat (grams)	22±10	10±4	-12	23±10	12±5	-11
Energy from PUFA (percentage)	6.6±1.94	4.6±0.7	-2.0	7.2±2.04	5.2±1.7	-2.0
PUFA (grams)	13.2±5.6	7.4±2.5	-6	14.2±6.1	8.1±3.3	-6
Energy from MUFA (percentage)	12.2±3.1	6.3±1.5	-5.93	13.1±2.7	8.9±2.6	-4.1
MUFA (grams)	25±10	10±4	-14	26±11	14.2±6.1	-12
Cholesterol (mg)	219±107	104±47	-1093	226±105	146±61	-79
Calcium (mg)	787±297	1,726±295	9373	730±245	801±242	69
Fiber (grams)	19.2±7.3	30.4±5.4	11.23	18±6.0	20.9±6.4	2.8
Potassium (mg)	2,748±754	3,980±662	1,2293	2,649±621	2,909±718	241
Sodium (mg)	3,110±947	2,274±462	-7903	3,049±971	2,697±758	-352
Magnesium (mg)	291±80	573±91	2823	277±72	290±74	12.1
Folate (ug)	275±105	649±113	3743	254±82	306±98	49

  

Men

Variables	Prepared Meal Plan Baseline (N=169 W, 114 M)	Prepared Meal Plan Treatment (N=163 W, 109 M)	Prepared Meal Plan Change N=163 W, 109 M)	Self-Selected Diet         Baseline (N=145 W, 132 M)	Self-Selected Diet  Treatment (N=142 W, 128 M)	Self-Selected Diet Change (N=142 W, 128 M)
Energy (kcal)	2,222±6224	1,849±388	-4775	2,492±7414	1928±421	-4593
Protein (grams)	92±254	86±15	-105,6	102±314	92±20	-65
Carbohydrate (grams)	267±86	287±60	-203	291±314	270±69	-18
Total Fat (grams)	87±334	37±14	-565,6	101±284	55±19	-405
Energy from fat (percentage)	37±7	18±3	-173	36±7	26±7	-10
Energy from Protein (percentage)	17±3	19±2	23	17±3	19±3	3
Energy from Carbohydrate (percentage)	48±8	62±4	143	47±8	56±7	9
Energy from SFA (percentage)	11.5±2.9	6.3±1.1	-5.13	11.9±2.9	8.2±2.7	-3.7
Saturated Fat (grams)	29±124	13±5	-185,6	34±14 4	18±7	-145
Energy from PUFA (percentage)	7.0±2.0	4.5±0.7	-2.5	7.3±2.1	5.3±1.4	-2.0
PUFA (grams)	17.4±8.04	9.2±2.8	-105,6	20.5±9.54	11.4±3.8	-85
Energy from MUFA (percentage)	13.5±3.0	6.1±1.3	-73	13.8±2.9	9.7±2.8	-4
MUFA (grams)	34±134	13±5	-235,6	39±154	21±8	-165
Cholesterol (mg)	310±136	114±51	-1935,6	347±156	219±82	-127
Calcium (mg)	886±323	2,125±399	-1,2363	951±407	1,054±396	125
Fiber (grams)	21.7±7.9	35.9±6.6	14.23	22.6±8.1	27.1±8.5	4.9
Potassium (mg)	3,248±933	4,780±845	1,5323	3,413±1,031	3,873±1,114	494
Sodium (mg)	3,880±1,1244	2,625±578	-1445,6	4,344±1,5364	3,794±1,140	-3805
Magnesium (mg)	345±109	692±132	3473	363±113	391±108	32
Folate (ug)	309±116	749±131	4413	335±131	415±150	86

¹All nutrient changes within treatment groups were significantly different from baseline, P<0.001, except for magnesium in the self-selected group women P<0.05, and self-selected group men, P<0.01; protein in prepared meal group women, P =0.48, and all men, P<0.01; carbohydrate in prepared meal group women and all men, P<0.05.
²x±SD
³Significantly different from the change in the self-selected diet P<0.05
⁴Significant difference in nutrient intake between groups, P<0.01
⁵Adjusted changes
⁶Significantly different from the adjusted change in the self-selected diet, P<0.05.

Changes in Endpoints Stratified by Sex and Treatment Group from Baseline to End of Treatment in Study Participants

		Prepared Meal Plan                                       Change (N=163 W, 109 M)	Self-Selected Diet                                                          Change (N=142 W, 128 M)
Variable: Women	Sitting systolic BP (mmHg)	-6.1±9.66	-4.5±9.62
	Sitting diastolic BB (mmgHg)	-3.4±5,42	-2.7±5.12
	Cholesterol (mmol/L)	-0.27±0.592	-0.22±0.522
	Triacylglycerol (mmol/L)	-0.07±1.34	-0.24±0.614
	LDL (mmol/L)	-.19±0.452	-0.12±0.433
	HDL (mmol/L)	-0.04±0.14	-0.03±0.134
	VLDL (mmol/L)	-0.03±00.61	-0.06±0.284
	Insulin (mmol/L)	-16.5±49.22	-18.7±91.84
	HbA1c (percentage)	-0.3±0.72	-0.2±0.62
	Plasma Glucose (mmol/L)	-0.6±1.92	-0.6±1.62
	Weight (kg)	-4.8±3.02,5	-2.8±2.82
Variable: Men	Sitting systolic BP (mm/Hg)	-7.0±8.52,6	-4.8±8.52
	Sitting diastolic BB (mmg/Hg)	-5.4±5.92,7	-3.2±5.12
	Cholesterol (mmol/L)	-0.39±0.572	-0.33±0.612
	Triacylglycerol (mmol/L)	-0.17±0.754	-0.21±0.824
	LDL (mmol/L)	-0.30±0.492	-0.21±0.462
	HDL (mmol/L)	-0.03±0.114	-0.02±0.10
	VLDL (mmol/L)	-0.09±0.38	-0.09±0.384
	Insulin (mmol/L)	-27.7±115.04	-16.7±67.2 4
	HbA1c (percentage)	-0.4±0.92	-0.5±0.92
	Plasma glucose (mmol/L)	-0.7±1.93	-0.9±2.42
	Weight (kg)	-4.5±3.62,5	-3.5±3.32

¹ x±SD. HbA1c (glycated hemoglobin)
^2-4Significant changes from baseline to the end of treatment were noted for all study endpoints except for triaclyglycerols and VLDL in women in the prepared meal plan group and HDL in men in the self-selected diet group:
² P <0.0001
³P<0.001
⁴P<0.05
^5-7Significant changes from baseline for diet group:
⁵P<0.0001
⁶P <0.05
⁷P<0.01.

Other Findings

• Across all definitions of compliance, participants following the prepared meal plan were significantly more compliant with their diet prescriptions than were participants in the self-selected diet group
• Energy compliance was achieved by 83% of prepared meal plan participants compared with 72% of the self-selected diet participants
• As expected percentage compliance increased in both groups as the definitions for fat compliance became more liberal. At 20% of energy from fat, 78% of the self-selected diet participants achieved compliance; at 25% of energy from fat 93% of the prepared meal plan participants compared with 56% of the self-selected diet group achieved compliance. At 30% energy from fat, 95% of prepared meal participants compared with 78% of self-selected diet participants achieved compliance.
• Participants following the prepared meal plan were better able to meet the NCEP/AHA Step 1 and 2 recommendations than was the self-selected diet group.

 

In conclusion, independent of the type of dietary intervention, compliant participants had significantly reduced blood pressures, plasma lipids and body weights across all levels of dietary compliance criteria compared with their non-compliant counterparts. The results of this study underscore the necessity of a high degree of compliance to achieve optimal reductions in CVD risk factors by dietary means. Creating programs that will optimize dietary compliance is critically important to reducing morbidity and mortality due to diet-sensitive chronic diseases. Prepared meal plans provide a simple and effective modality for meeting the plethora of dietary guidelines recommended for prevention and treatment of chronic diseases, for improving dietary compliance and for reducing CVD risk.

Industry:

Campbell's Soup Co. Food Company:

Strengths of the study include, strong research design with statistical as well as clinical significance, use of a large sample size, comparable study groups, and discussion of study limitations which might effect study outcomes. A limitation of this study, however is that diet compliance was based largely on analysis of three-day food records which are not necessarily completed with 100% accuracy. For a variety of reasons, actual food intakes tend to be underreported which could contribute to false-positive results. Authors also neglected to mention whether blinding was used in any portion of this study which would eliminate introduction of bias.