Does having excess bodyfat adversely affect muscular gains? That was the focus of a recent study featuring 140 normal-weight and 81 overweight men and women who hadn’t trained in more than a year.1 They began training twice a week for 12 weeks, doing one-arm biceps curls. The researchers adjusted the training responses for bodyweight and initial values and found that the normal-weight group had made better gains than the overweight group. That led them to conclude that there’s something about being fat that hinders muscular gains. The question is: what is it about having excess bodyfat that would hinder muscle gains?The answer is inflammation. Fat,far from being just inactive tissue, releases over 100 chemicals, collectively known as "adopikines." Most of these substances, which are proteins, promote inflammation. This is the great danger of having too much bodyfat, since excess inflammation is the cornerstone of most serious diseases, such as cardiovascular disease and cancer. But excess inflammation also interferes with amino acid uptake into muscle, and promotes muscle breakdown (catabolism).Most obese people are also insulin insensitive,which adds to the problem, since insulin provides anti-catabolic effects in muscle, as well as aids in muscle uptake of amino acids necessary for muscle protein synthesis.
From a practical standpoint, this means that those with higher levels of bodyfat should initially focus on losing that excess fat through diet and exercise, then switch to a more "anabolic" style of training designed to build extra lean mass.
1 Kelsey, B., et al. (2004). Adiposity alters muscle strength and size responses to resistance training in healthy men and women. Med Sci Sports Exerc. 36:S352.
©,2011 Jerry Brainum.Any reprinting in any type of media, including electronic and foreign is expressly prohibited.
