A randomized study of dietary composition during weight-loss maintenance: Rationale, study design, intervention, and assessment

作者：Ebbeling Cara B; Klein Gloria L; Luoto Patricia K; Wong Julia M W; Bielak Lisa; Eddy Ralph G; Steltz Sarah K; Devlin Courtenay; Sandman Megan; Hron Bridget; Shimy Kim; Heymsfield Steven B; Wolfe Robert R; Wong William W; Feldman Henry A; Ludwig David S

来源：Contemporary Clinical Trials, 2018, 65: 76-86.

DOI：10.1016/j.cct.2017.12.004

• Dietary intervention
• Weight-loss maintenance
• Energy expenditure
• Obesity
• Feeding protocol
• Research partnership

Background: While many people with overweight or obesity can lose weight temporarily, most have difficulty maintaining weight loss over the long term. Studies of dietary composition typically focus on weight loss, rather than weight-loss maintenance, and rely on nutrition education and dietary counseling, rather than controlled feeding protocols. Variation in initial weight loss and insufficient differentiation among treatments confound interpretation of results and compromise conclusions regarding the weight-independent effects of dietary composition. The aim of the present study was to evaluate three test diets differing in carbohydrate-to-fat ratio during weight-loss maintenance.
Design and dietary interventions: Following weight loss corresponding to 12 +/- 2% of baseline body weight on a standard run-in diet, 164 participants aged 18 to 65 years were randomly assigned to one of three test diets for weight-loss maintenance through 20 weeks (test phase). We fed them high-carbohydrate (60% of energy from carbohydrate, 20% fat), moderate-carbohydrate (40% carbohydrate, 40% fat), and low-carbohydrate (20% carbohydrate, 60% fat) diets, controlled for protein content (20% of energy). During a 2-week ad libitum feeding phase following the test phase, we assessed the effect of the test diets on body weight.
Outcomes: The primary outcome was total energy expenditure, assessed by doubly-labeled water methodology. Secondary outcomes included resting energy expenditure and physical activity, chronic disease risk factors, and variables to inform an understanding of physiological mechanisms by which dietary carbohydrate-to-fat ratio might influence metabolism. Weight change during the ad libitum feeding phase was conceptualized as a proxy measure of hunger.

• 出版日期2018-2