Energy Balance Weight Regulation Study

Phase 2

Completed

• Conditions: Obesity
• Interventions: Other: Ad libitum low carbohydrate diet; Other: Ad libitum High Complex Carbohydrate Diet; Other: Energy-restricted high complex carbohydrate diet

• Registration Number: NCT00619008
• Lead Sponsor: National Center for Complementary and Integrative Health (NCCIH)

Brief Summary

The purpose of this study is to test the hypothesis that a low-carbohydrate diet will impact hormones and other factors that regulate appetite and energy balance, and result in lower energy intake and greater weight loss, than a high complex carbohydrate diet.

Detailed Description

The rising epidemic of obesity in the United States is accompanied by widespread public use of low carbohydrate diets for weight loss. The popularity of these diets is due partly to the promise of a "metabolic advantage" that promotes faster weight loss without an overriding sense of hunger. If this claim is true, we hypothesize that a low-carbohydrate diet will impact hormones and other factors that regulate appetite and energy balance, and result in lower energy intake and greater weight loss, than a high complex carbohydrate diet. To test this hypothesis, we will conduct a randomized, controlled feeding trial in which obese adults will be randomly assigned to one of three interventions: a low-carbohydrate-ad libitum diet, a high-carbohydrate-ad libitum diet, or a high-carbohydrate-energy-restricted diet. The low-carbohydrate diet will be modeled after the Induction Phase of the Atkins Diet. The high carbohydrate diet will be based on the "Dietary Approaches to Stop Hypertension (DASH)" diet. Participants will eat a standardized weight maintenance diet for 3 weeks. Then, for 6-weeks, participants assigned to either ad libitum group will be given their assigned diet at 120% of there estimated energy needs to maintain weight and allowed to eat as much as desired. Participants assigned to the energy-restricted group will be provided a DASH diet at 67% of their estimated energy needs to maintain weight and asked to eat all foods provided. Food intake will be measured daily. Body weight and hunger and satiety scores will be measured three times a week. Body composition and energy expenditure will be measured before and after the intervention. 24-hour profiles of hormones and other factors that influence central appetite and weight regulation (insulin, leptin, ghrelin, PYY, GLP-1) will be measured before, and on first and last days of the intervention, to compare acute and chronic metabolic effects of the diets. The analysis of primary outcomes will be based on repeated measures and longitudinal models methodology. This study offers a unique opportunity to explore how extreme differences in dietary composition, before and after weight loss, affect components of energy balance and markers of central appetite and weight regulation. These results will be used to design hypothesis-driven studies of the identified mediators of appetite and weight regulation in response to dietary manipulation.

Study Timeline

• Study Start: 2005-04
• Study First Submitted: 2008-02-15
• Study First Submitted QC: 2008-02-15
• Study First Posted: 2008-02-20
• Primary Completion: 2008-09
• Study Completion: 2008-09
• Status Verified: 2008-10
• Last Update Submitted: 2008-10-02
• Last Update Posted: 2008-10-03

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 35

Inclusion Criteria

• BMI 30-50 kg/m2
• Age 21-65 years
• Relative good health

Exclusion Criteria

• Major debilitating mental of physical illness that would interfere with participation
• Renal or hepatic disease, diabetes, gallbladder disease, untreated hyper-or hypothyroidism, poorly controlled hypertension (>3 HT medications)
• Use of lipid lowering medications
• Current of recent (within 12 mo) pregnancy or lactation
• Current excessive use of alcohol
• Current/recent (within 1 year)use of tobacco products
• Food allergies, food restrictions, or food preferences that are inconsistent with the research diets

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
1	Ad libitum low carbohydrate diet	Ad libitum low carbohydrate diet
2	Ad libitum High Complex Carbohydrate Diet	Ad libitum high complex carbohydrate diet
3	Energy-restricted high complex carbohydrate diet	Energy-restricted high complex carbohydrate diet

Primary Outcome Measures

Name	Time	Method
24-hour profiles and AUCs of hormones and other factors that influence central appetite and weight regulation (insulin, leptin, ghrelin, PYY, GLP-1).	Week 2, week 3 and week 9 of intervention

Secondary Outcome Measures

Name	Time	Method
Energy intake, hunger and satiety ratings	week 2, 3, and 9 of intervention

Trial Locations

Locations (1)

Oregon Health & Science University; 🇺🇸 Portland, Oregon, United States