The BREAK study protocol: Effects of intermittent energy restriction on adaptive thermogenesis during weight loss and its maintenance

• Published in: PloS one Vol. 18; no. 11; p. e0294131
• Main Authors: Cortez, Filipa M, Nunes, Catarina L, Sardinha, Luís B, Silva, Analiza M, Teixeira, Vítor H
• Format: Journal Article
• Language: English
• Published: San Francisco Public Library of Science 13-11-2023; Public Library of Science (PLoS)
• Subjects: Analysis; Biology and Life Sciences; Body composition; Body mass; Body weight loss; Corticosteroids; Diet; Energy; Energy balance; Energy expenditure; Evidence-based medicine; Exercise; Fat-free body mass; Hormones; Intervention; Investigations; Leptin; Maintenance; Medical research; Medicine and Health Sciences; Medicine, Experimental; Metabolism; Nutrition research; Obesity; Overweight; Physical fitness; Physiological aspects; Social networks; Study Protocol; Thermogenesis; Thyroid; Thyroid gland; Weight control; Weight loss; Weight loss maintenance; Portugal
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0294131

Adaptive thermogenesis, defined as the decrease in the energy expenditure components beyond what can be predicted by changes in body mass stores, has been studied as a possible barrier to weight loss and weight maintenance. Intermittent energy restriction (IER), using energy balance refeeds, has been pointed out as a viable strategy to reduce adaptive thermogenesis and improve weight loss efficiency (greater weight loss per unit of energy deficit), as an alternative to a continuous energy restriction (CER). Following a randomized clinical trial design, the BREAK Study aims to compare the effects of IER versus CER on body composition and in adaptive thermogenesis, and understand whether participants will successfully maintain their weight loss after 12 months. Seventy-four women with obesity and inactive (20-45 y) will be randomized to 16 weeks of CER or IER (8x2 weeks of energy restriction interspersed with 7x1 week in energy balance). Both groups will start with 2 weeks in energy balance before energy restriction, followed by 16 weeks in energy restriction, then 8 weeks in energy balance and finally a 12-month weight maintenance phase. Primary outcomes are changes in fat-mass and adaptive thermogenesis after weight loss and weight maintenance. Secondary outcomes include weight loss, fat-free mass preservation, alterations in energy expenditure components, and changes in hormones (thyroid function, insulin, leptin, and cortisol). We anticipate that The BREAK Study will allow us to better understand adaptive thermogenesis during weight loss and weight maintenance, in women with obesity. These findings will enable evidence-based decisions for obesity treatment.