Recent interest has emerged on the role of hypoenergetic very low calorie diets (VLCD) in managing overweight and obese people with or without type 2 diabetes. However, VLCD results in 20-30% of mass lost as lean body mass (LBM) besides adipose tissue. Since LBM in the form of skeletal muscle plays an important role for maintaining whole-body metabolic health and represents a vast protein store, better understanding of the mechanisms of VLCD induced weight loss is very important. In a recent systematic review, the investigators observed that information on the subject is scarce. Early studies with VLCD, using poor quality protein supplements showed that VLCD was associated with an increased risk of adverse mortality outcome mainly due to cardiac muscle atrophy. Although current VLCDs are safer, concerns regarding preservation of LBM persist. This is because, in middle-aged (and older) people who are already suffering the early stages of sarcopenia at approximately 0.5-1%/y from the age of ~40y, VLCD may result in additional significant muscle mass loss. Low muscle mass, especially in older individuals is associated with increased mortality, dynapenia (reduced muscle function) and numerous metabolic conditions. Exercises remain the most effective means by which to maintain and increase muscle mass through stimulation of muscle protein synthesis (MPS). Although studies have shown that losses of LBM during a VLCD can be attenuated with the inclusion of resistance exercise training (RET) [5], the mechanism by which VLCD (with and without exercise) effects MPS is poorly defined. The investigators also know now that high intensity interval training (HIIT) improves LBM, cardiac and metabolic function, yet no study has clarified the outcome of HIIT with VLCD on MPS and LBM. The investigators will investigate the different effects of VLCD with RET, VLCD with HIIT, and VLCD alone on MPS and overall metabolic function in overweight middle-aged males.