INS and obesity due to melanocortin 4 receptor deficiency: 2016). Muscle mass is determined by the balance between muscle protein synthesis and muscle protein breakdown. Obesity appears to alter these two processes. For example, leg protein turnover (synthesis and breakdown) measured during insulin and amino acid infusion was found to be reduced in obese older men (Murton et al. 2015). Furthermore, the stimulatory effect of protein feeding on myofibrillar muscle protein synthesis was diminished in sedentary overweight and obese individuals when compared with healthy‐weight controls (Beals et al. 2016).