The Physiological Basis for Weight Recidivism Following Severe Caloric Restrictive Diet Therapies: A Molecular Rationale for Exercise-and Nutrition-Based Treatment Optimization

Medically prescribed very-low calorie diet (VLCD) programs have shown efficacy in producing clinically significant weight-loss in obese patients.  This loss in bodyweight (BW), however, cannot be solely accounted for by reduced adiposity, but also significant deficits in lean tissue.  With respect to these frequently reported weight-loss patterns for lean body mass (LBM), the potential for optimum weight-loss as well as sustainable weight-maintenance is adversely affected on a number of levels.  Lowered resting metabolic rate (RMR), neuromuscular impediments, and poor physical function have been reported to occur as a result of reduced LBM.  Any of these factors taken together with a dramatic loss of lean tissue would be a condition that is conducive to impeded fat reduction, weight-regain, and relapses of prior health complications.  Therefore, the main purpose of this review is 3 fold: 1) to comprehensively discuss the molecular and morphological adaptations to VLCD treatment in lean and fat tissues, 2) to provide molecular- to practical-based rationale for systematic exercise applications in VLCD treatments, and 3) to discuss current research limitations and future research implications.