Due to its mechanical and metabolic functions, muscle loss leads to resistance to weight loss during caloric restriction, particularly in patients with obesity. The recent discovery of a "gravitational" homeostatic system, induced by an additional load to body weight, suggests the existence of a new weight control mechanism. Such a "gravitostat" would ensure a form of weight homeostasis mediated by afferent signals originating from osteocytes in response to gravity perception. This hypothesis, initially derived from animal studies, has more recently been tested in humans. It shows that "activation of the gravitostat" through artificial increases in body weight facilitates body weight reduction without affecting lean mass (LM). Therefore, this "gravitostat" could contribute to preserving LM despite the loss of fat mass , whereas its decline may compromise muscle mass and function after bariatric surgery, despite undeniable improvements in comorbidities.
The present study aims to reduce the "metabolic load" (i.e., decreasing insulin resistance and inflammation) to promote muscle protein anabolism, while maintaining the "mechanical load" (by preserving initial body weight during weight loss induced by bariatric surgery) in order to activate the "gravitostat" and preserve muscle mass and function.
Currently, there are no clear recommendations or strategies to prevent muscle loss in patients who have undergone bariatric surgery. This simple concept, applied during drastic muscle loss, should help improve muscle health.