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.
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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