Are methods of estimating fat-free mass loss with energy-restricted diets accurate?

• Published in: European journal of clinical nutrition 2023-05, Vol.77 (5), p.525-531
• Main Authors: Heymsfield, Steven B., Ludwig, David S., Wong, Julia M. W., McCarthy, Cassidy, Heo, Moonseong, Shepherd, John, Ebbeling, Cara B.
• Format: Article
• Language: English
• Subjects: 59/57; 631/443/319; 692/308/53; Body Composition; Body fat; Body measurements; Body water; Body weight; Body weight loss; Bone density; Bone mass; Carbohydrates; Clinical Nutrition; Clinical trials; Diet; Diet, Reducing; Dietary restrictions; Epidemiology; Fat-free body mass; Female; Humans; Internal Medicine; Low carbohydrate diet; Male; Medicine; Medicine & Public Health; Mens health; Metabolic Diseases; Nutrient deficiency; Obesity; Overweight; Public Health; Weight control; Weight Loss; Weight loss measurement; Womens health
• ISSN: 0954-3007; 1476-5640
• DOI: 10.1038/s41430-022-01203-5

Background/Objectives Fat-free mass (FFM) often serves as a body composition outcome variable in weight loss studies. An important assumption is that the proportions of components that make up FFM remain stable following weight loss; some body composition models rely on these “constants”. This exploratory study examined key FFM component proportions before and following weight loss in two studies of participants with overweight and obesity. Subjects/Methods 201 men and women consumed calorie-restricted moderate- or very-low carbohydrate diets leading to 10–18% weight loss in 9–15 weeks. Measured total body fat, lean mass, bone mineral, total body water (TBW), and body weight at baseline and follow-up were used to derive FFM and its chemical proportions using a four-component model. Results A consistent finding in both studies was a non-significant reduction in bone mineral and a corresponding increase ( p