When I competed in bodybuilding contests, a common practice involved what we called "junk days."The procedure was as follows: you would stay on a strict diet, most often one that restricted carbohydrate intake, 6 days a week. On the seventh day, you would have your junk day. As the name implied, this meant eating everything and anything that you wanted. Some elite bodybuilding trainers back then advocated junk days, but they would suggest eating only one high carbohydrate meal every few days. The purpose of this was to replenish the muscle glycogen or stored carbohydrate that was depleted during low carb diets. This not only produced a noticeable energy surge but also provoked a release of insulin. The latter was significant because insulin was an anti-catabolic hormone that served to protect muscle mass under stringent dieting conditions. Insulin also opposed the catabolic effects of the adrenal hormone, cortisol. On low-carb diets, cortisol levels tended to rise, especially in the later stages of the diet. Even those bodybuilders who consumed massive amounts of food on their junk days showed few side effects. These side effects were usually temporary, consisted of weight gain and water retention. Since the usual junk day was on Sunday, those side effects would appear on Monday, but be gone by Wednesday after going back on the low carb diet.
The junk days not only provided some physiological effects, such as the heightened insulin release but also provided some significant psychological effects. Among these was greater compliance to the stringent low-carb diet. Knowing that a junk day was coming allowed most bodybuilders to bear the mental stress of staying on a very low-carb diet. In short, it gave us something to look forward to. More recently, lower carb diets have been advocated for diets designed to increase muscular mass. Typical of such diets are the "Anabolic diet," designed by physician and champion powerlifter, Mauro Di Pasquale. Mauro's diet advocated less than 40 grams of carbs 5 days a week, followed by a reversal of carb intake on weekends. His rationale for this program was that consuming a very low carb, higher protein intake that also featured a lot of fat consumption would maximize anabolic hormones, such as testosterone and growth hormone. It is true that eating more fat does promote a greater synthesis of testosterone up to a point. Restricting carbohydrates would favor a greater growth hormone release since growth hormone release is blunted by carbohydrate intake.
So it appears that including a junk day during otherwise stringent dieting periods is relatively harmless. But another common practice of many bodybuilders who've dieted strictly for months in preparation for a contest appearance is to go on an eating binge right after the contest. It's not uncommon to pack on 20 pounds in a week following a post-contest eating binge. I recall being in the studio of a well-known bodybuilding photographer where . . .