According to a new study published in The Journal of Nutrition percent fat-free mass loss, following diet-induced weight loss, is not a significant predictor of weight regain at 1-year in men and women with obesity.

A growing body of evidence suggests that fat-free mass plays a role in the drive to eat and is likely to modulate energy intake and body weight via its effects on energy expenditure and through feedback signaling between fat-free mass and appetite control regions of the brain. Therefore, the loss of fat-free mass resulting from energy-restricted diets may contribute to weight regain, not only due to lower energy expenditure, but also to the body’s attempt to restore fat-free mass by overeating. Although the exact mechanisms through which fat-free mass loss modulates weight regain remain unclear, the hunger stimulating hormone ghrelin is a potential candidate.  To bridge this knowledge gap, and in a collaborative effort with the Norwegian University of Science and Technology, Martins (University of Alabama at Birmingham) and colleagues performed a secondary analysis aiming to determine if percent fat-free mass loss following weight loss predicts weight regain and to investigate the association between percent fat-free mass loss and changes in appetite markers in men and women with obesity.

Study participants underwent 8 weeks of a very low energy diet (550-600 kcal/week) followed by 4 weeks of gradual refeeding and a 9-month maintenance program. Outcome variables, which included body weight, body composition, ketosis, appetite-related hormones, and subjective appetite feelings, were measured at baseline, week 9, and 1 year.  Subjective feelings of appetite (hunger, fullness, desire to eat, and prospective food consumption) and plasma concentrations of appetite-related hormones were measured in fasting and every 30 minutes after a standardized breakfast for 2.5 hours.

Percent fat-free mass loss was not a significant predictor of weight regain at 1 year in individuals with obesity. However, a greater percent fat-free mass loss was accompanied by a greater increase in the secretion of ghrelin, a hunger hormone, under ketogenic conditions, suggesting a link between fat-free mass and appetite regulation. 

References

Martins C, Nymo S, Goutinho SR, Rehfeld JF, Hunger GR, Gower BA. Association between Fat-Free Mass Loss, Changes in Appetite, and Weight Regain in Individuals with Obesity. The Journal of Nutrition, Volume 153, Issue 5, May 2023, Pages 1330-1337, doi.org/10.1016/j.tjnut.2023.03.026.

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Kathy Beerman, PhD

Dr. Kathy Beerman teaches in the School of Biological Sciences at Washington State University. The author of several published articles, she is interested in research that focuses on the efficacy of a novel approach to treating iron deficiency anemia in rural regions of Guatemala and Ecuador. Dr. Beerman teaches an undergraduate nutrition course for health majors, as well as a course that prepares students to participate in a 10-day medical mission to Guatemala. Since joining the faculty at Washington State University in 1990, she has been the recipient of several teaching awards (the Burlington Northern Faculty Meritorious Achievement in Teaching Award, the R.M. Wade Foundation Award for Excellence in Teaching, and the Sahlin Faculty Excellence Award for Instruction). More recently, she received the CAS Outstanding Achievement Award in International Activities (2017) and the President’s Award for Leadership (2018). Other scholarly activities include co-author of two introductory nutrition textbooks (Nutritional Sciences: From Fundamentals to Food and NUTR).