Despite the prodigious guts, which look capable of launching a reptilian creature, like a scene from the movie “Alien,” the skin is so thin and subcutaneous fat so low that muscles, veins and tendons are readily apparent. Those in the know are aware of the direct causes of abdominal distension, while others guess. It’s important to dispel irrelevant factors, as they serve only to confuse the issue. The abdominal distension seen in today’s bodybuilders isn’t due to intestinal gas, obesity due to overeating or use of powerlifting movements. Today’s bodybuilders are very sophisticated in regard to diet and it’s extremely unlikely that any, let alone every pro would be downing grams of maltitol or fiber laxatives immediately before walking on stage. As was stated earlier, the bodybuilders of today have extremely low subcutaneous body fat. The guts aren’t due to generalized obesity. In the off-season, many of these athletes relax their standards and tend to accumulate body fat, some to the point of obesity, but this isn’t a factor on stage during competition.

Causes for the Big Gut
While power movements are still part of the training regimen for many bodybuilders, such moves don’t account for the gut. Powerlifters tend to have a more portly appearance, but this is due to higher body fat levels, low aerobic capacity and weakening and/or stretching of the abdominal wall from repeated high intra-abdominal pressure exercises. Powerlifters may also acquire hernias, which can deform the abdominal wall.5 The primary factors leading to the dramatic belly bulging are the abusive levels of GH and insulin use.

GH, human growth hormone, was originally provided in very limited supply to dwarf children as it was sourced from the brains of cadavers.6 During the 1970’s, advances in genetic engineering allowed for the relatively unlimited production growth hormone using recombinant technology.7 By the late 1980’s, GH was readily available and being used by athletes in many sports, including football, cycling and bodybuilding.8 GH was found to be effective in promoting connective tissue health, speeding recovery, reducing body fat and enhancing anabolic growth.9

As is the case with most drugs, bodybuilders applied trial and error to determine the optimal dosing schedule of GH for achieving maximum growth. During this time, endorsements and trophies were won by those who achieved the most exaggerated growth. This system of rewards promoted the use of excessively high doses of GH, upward to 36 International Units (IU) per day.
Despite the relative benefits of extreme muscular growth, bodybuilders began to develop adverse side effects. For those familiar with the field of endocrinology, the study of hormones’ effects on the body, these side effects were not unexpected. Strange, disfiguring growths of the ears, nose and jaw change facial shape, hands and feet enlarge and the abdomen protrudes being pushed outward by the growth of thoracic (chest) and abdominal (gut) organs.10,11