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Predicting Adherence to a Heart-Healthy Diet in Lean and Obese Individuals

Is Non-Adherence Unique to Weight-Loss? Predictors of Adherence to a Heart-Healthy Diet in Lean vs. Obese Individuals

Status
Completed
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT01862796
Enrollment
100
Registered
2013-05-24
Start date
2013-05-31
Completion date
2018-05-22
Last updated
2019-08-15

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Obesity, Overweight

Keywords

Food Intake, Weight Loss, Compliance

Brief summary

Background: \- Sticking to a diet plan can be difficult, but is important for many different health reasons. Some people seem to have a harder time following and sticking to a diet plan than others. It is not clear whether people of different weights (lean or obese) might have differences in the way they adhere to diet plans. Researchers want to study three different groups of people based on their body mass index (BMI), which measures people based on their weight and height. The study will place the participants on a 6-week diet and see how well they follow the diet. The information from this study may help develop better weight-loss plans and healthy diet ideas. Objectives: * To understand what factors affect adherence to a diet plan. * To collect information for future studies that may improve people's ability to stick to diets. Eligibility: \- Individuals at least 18 years of age who are lean (BMI between 18.5 and 25) or obese (BMI greater than 30). Design: * Participants will be screened with a physical exam and medical history. Blood and urine samples will be collected. They will have a full-body scan to measure fat and muscle. They will also answer questions on eating behaviors, mood, and desire to change eating patterns. * Participants will be separated into three groups. Each group will have a different diet. The lean group will have a heart-healthy diet designed to maintain the same weight. One of the obese groups will also have a heart-healthy diet designed to maintain the same weight. The other obese group will have a heart-healthy weight loss diet. In all groups, all food will be provided by the study doctors. Participants should not eat any food other than that provided for the study. * Everyone will start with a 1-week food testing period to find the right number of calories for each group. After this first week, participants will attend one diet counseling session per week and will be contacted randomly once a week to check on the foods they have had in the past 24 hours. Participants will complete daily food diaries on paper as well as daily food records using a smart phone. * Participants will come to the clinic twice a week to pick up the diet food. On one of those days, they will also have their counseling session. * The study will last for 6 weeks. At the final study visit, participants will repeat the tests from the screening study.

Detailed description

Adherence, or sticking to your diet is important for successful initial weight loss and keeping off the weight over the long term (1). While early behavioral and dietary adherence have been associated with greater weight loss, sticking to a diet plan is difficult. It is not clear if adherence to any diet plan (even one which does not produce weight loss) is hard or whether people who are overweight have more difficulty with adhering to diet plans compared to people who are relatively lean. The main aim of this study is to evaluate dietary adherence in 3 groups of individuals participating in a 6-week heart-healthy dietary intervention program. Two groups \[1 (BMI \< 25 kg/m(2)) and 2. Obese (BMI greater than or equal to 30 kg/m(2))\] will receive a heart-healthy diet designed to maintain their weight, and the third group \[3. Obese\] will be given a heart-healthy diet that is 35% less than their daily calorie needs to lose weight. Participants will attend one counseling session per week and will be contacted randomly 1x/week by study staff for completion of a 24-hour dietary recall. They will complete daily food diaries and daily records using smart-phones. Prior to starting the assigned heart-healthy dietary intervention, participants will complete questionnaires that include questions about how motivated they are to follow a diet, lose weight, and change eating patterns. These findings may help us understand what factors affect adherence, and help us design weight loss studies that improve people's ability to stick to diet interventions.

Interventions

BEHAVIORALUnderfeeding diet

Heart healthy diet with 35% reduced calories

BEHAVIORALWeight maintaining diet

Heart healthy weight-maintaining diet

Sponsors

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Lead SponsorNIH

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
Yes

Inclusion criteria

-INCLUSION CRITERIA: 1. BMI * BMI greater than or equal to 30 kg/m(2) for the obese WMEN and UF groups but body weight less than 350 pounds to accommodate the DXA scanner * BMI less than or equal to 25 kg/m(2) (and BMI greater than or equal to 18.5 kg/m(2)) for the lean WMEN group 2. Age greater than or equal to 18 years. Minors under the age of 18 will be excluded because growth and pubertal issues are significant parameters that could affect our outcomes and also because the time requirements of the study are such that they would interfere with school schedules. Participants must be healthy, as determined by medical history, physical examination, and laboratory tests. 3. Weight stable (plus or minus 2 percent) for last 3 months

Exclusion criteria

Candidates will be screened by phone to exclude those with BMI greater than or equal to 26 kg/m(2) and BMI less than or equal to 29 kg/m(2), significant health problems, including cancer, hypertension, diabetes, current and past 3-month use of certain prescribed medications, especially those that could affect body weight, such as antidepressants and stimulants as well as smoking, or excess alcohol (greater than 3 drinks/d). Women must not be pregnant or lactating, and be at least 1 year postpartum. Candidates with a history of psychotic disorder or hospitalization for psychiatric illness within the past 1 year will not be eligible. They will need to be weight stable for the past 3 months (plus or minus 2 percent) and cannot be in treatment for obesity or currently receiving psychotherapy. Individuals who meet criteria according to the phone screen will be invited to come to the unit for a screening visit and their screening sheets are placed in a locked filing cabinet. Forms from potential volunteers who are ineligible are shredded.

Design outcomes

Primary

MeasureTime frameDescription
Adherence ScoreAverage over 6 weeksAn adherence score is calculated each week by summing 7 measurements of adherence and dividing by 21, the maximum score, with range from 0 (no adherence) to 1 (perfectly adherent). For each of the 7 measures a higher score means better adherence: \[1\] Attendance (0-2), \[2\] Food diaries (0-3), \[3\] 24-hour food recall via interview (0-3), \[4\] computer survey (0-3), \[5\] 24-hour food recall via interview (0-3), \[6\] Ecological momentary assessment (0-6), and \[7\] On time arrival for session (0-1). The final score is calculated as the average of the six weekly scores.

Secondary

MeasureTime frameDescription
Change in Weight From Baseline to 6 Weeks6 weeksWeight loss from baseline, calculated as weight at 6 weeks - weight at baseline

Countries

United States

Participant flow

Pre-assignment details

100 participants were assessed for eligibility, 30 were ineligible and 9 did not complete the run-in phase. Sixty-one were assigned to groups.

Participants by arm

ArmCount
Obese Underfeeding (UF)
Obese randomized to received a 35% calorie reduced diet Underfeeding diet: Heart healthy diet with 35% reduced calories
19
Obese Weight Maintaining (WMEN)
Randomized to receive a weight-maintaining diet Weight maintaining diet: Heart healthy weight-maintaining diet
18
Lean Weight Maintaining (WMEN)
Normal weight individuals receiving a weight-maintaining energy needs diet Weight maintaining diet: Heart healthy weight-maintaining diet
23
Total60

Withdrawals & dropouts

PeriodReasonFG000FG001FG002
Overall StudyProhibited medications001

Baseline characteristics

CharacteristicTotalObese Underfeeding (UF)Obese Weight Maintaining (WMEN)Lean Weight Maintaining (WMEN)
Age, Continuous48.3 years
STANDARD_DEVIATION 14.1
45.3 years
STANDARD_DEVIATION 16.8
49.8 years
STANDARD_DEVIATION 13.1
49.7 years
STANDARD_DEVIATION 12.5
BMI (kg/m^2)30.9 kg/m^2
STANDARD_DEVIATION 8.5
38.0 kg/m^2
STANDARD_DEVIATION 8.7
33.5 kg/m^2
STANDARD_DEVIATION 4
22.9 kg/m^2
STANDARD_DEVIATION 1.8
Height, cm166.5 cm
STANDARD_DEVIATION 9.9
170.5 cm
STANDARD_DEVIATION 10.4
161.7 cm
STANDARD_DEVIATION 9.4
166.9 cm
STANDARD_DEVIATION 8.6
Race/Ethnicity, Customized
Race/Ethniticy
American Indian or Alaskan Native
16 Participants7 Participants8 Participants1 Participants
Race/Ethnicity, Customized
Race/Ethniticy
Asian
1 Participants0 Participants0 Participants1 Participants
Race/Ethnicity, Customized
Race/Ethniticy
Black or African American
5 Participants0 Participants2 Participants3 Participants
Race/Ethnicity, Customized
Race/Ethniticy
Caucasian
29 Participants9 Participants3 Participants17 Participants
Race/Ethnicity, Customized
Race/Ethniticy
Hispanic/Latino
8 Participants2 Participants5 Participants1 Participants
Race/Ethnicity, Customized
Race/Ethniticy
Native Hawaiian of Pacific Islander
1 Participants1 Participants0 Participants0 Participants
Region of Enrollment
United States
60 participants19 participants18 participants23 participants
Sex: Female, Male
Female
37 Participants10 Participants13 Participants14 Participants
Sex: Female, Male
Male
23 Participants9 Participants5 Participants9 Participants
Weight, kg86.1 kg
STANDARD_DEVIATION 27.3
111.0 kg
STANDARD_DEVIATION 29.1
88.1 kg
STANDARD_DEVIATION 15.3
63.9 kg
STANDARD_DEVIATION 8

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
EG002
affected / at risk
deaths
Total, all-cause mortality
0 / 190 / 180 / 23
other
Total, other adverse events
0 / 190 / 180 / 23
serious
Total, serious adverse events
0 / 190 / 180 / 23

Outcome results

Primary

Adherence Score

An adherence score is calculated each week by summing 7 measurements of adherence and dividing by 21, the maximum score, with range from 0 (no adherence) to 1 (perfectly adherent). For each of the 7 measures a higher score means better adherence: \[1\] Attendance (0-2), \[2\] Food diaries (0-3), \[3\] 24-hour food recall via interview (0-3), \[4\] computer survey (0-3), \[5\] 24-hour food recall via interview (0-3), \[6\] Ecological momentary assessment (0-6), and \[7\] On time arrival for session (0-1). The final score is calculated as the average of the six weekly scores.

Time frame: Average over 6 weeks

ArmMeasureValue (MEAN)Dispersion
Obese Underfeeding (UF)Adherence Score0.57 score on a scaleStandard Deviation 0.17
Obese Weight Maintaining (WMEN)Adherence Score0.54 score on a scaleStandard Deviation 0.18
Lean Weight Maintaining (WMEN)Adherence Score0.59 score on a scaleStandard Deviation 0.1
Secondary

Change in Weight From Baseline to 6 Weeks

Weight loss from baseline, calculated as weight at 6 weeks - weight at baseline

Time frame: 6 weeks

ArmMeasureValue (MEAN)Dispersion
Obese Underfeeding (UF)Change in Weight From Baseline to 6 Weeks-3.14 kgStandard Deviation 2.76
Obese Weight Maintaining (WMEN)Change in Weight From Baseline to 6 Weeks-1.64 kgStandard Deviation 2.41
Lean Weight Maintaining (WMEN)Change in Weight From Baseline to 6 Weeks-0.54 kgStandard Deviation 1.53

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026