The Role Of Insulin In Body Composition: Evience Based Recommendations For Resistance Training Applications

Abstract

Insulin’s effects and practical uses are well documented for diabetes patients, but implications of endogenous insulin levels are seldom used functionally in other settings. This literature review examines existing literature describing the ramifications of insulin activity on body composition, and seeks to propose protocols – through nutrition and training – for improving body composition (lowering body fat, increasing lean body mass) based on these ramifications. It appears that a diet that elicits low insulin responses will promote insulin sensitivity, thereby attenuating insulin-dependent adipose tissue anabolism. When combined with a resistance training regimen, insulin sensitivity improves further; resistance training also elicits higher levels of glucose transporter 4 (GLUT-4) expression and translocation across muscle cell membranes. This phenomenon favorably affects nutrient partitioning toward lean body mass, preferentially allocating post-exercise nutrients to skeletal muscle tissue as opposed to adipose tissue. Once more researched and refined, applications include: clinicians wishing to lower BMI and improve body composition of patients; recreational athletes wishing to improve body composition for personal/aesthetic reasons; athletes of all levels for whom body composition is tantamount to performance and/or weight class – e.g. divers, swimmers, fighters, gymnasts, etc.