Many bodybuilding opinions exist in regards to producing maximum muscle mass with the smallest possible body fat level, with weight lifters experimenting with diet variables, including whether food is consumed prior to sleep, in order to enhance progress. Some bodybuilders understand the benefit of a bedtime meal, but others avoid food prior to sleep, especially bodybuilders who either gain fat quickly when attempting to build muscle mass, or who are focusing specifically on fat loss, and wish to amplify the speed of results.

The theory is that eating prior to sleep encourages fat gain, and although there is no direct correlation between eating late and fat gains, because many diet plans are structured with poorly chosen calories and carbohydrates, not to mention improper meal division, which can detract from building a more efficient metabolism, eating before sleep encourages fat storage for many, and some in the bodybuilding world classify later eating as destructive towards body fat percentage.

The common mistake made is to either use greater than necessary carbohydrates for a bedtime meal, or consume a food intake that is beyond the body's core requirements for muscle growth or preservation, which then clearly will result in fat gain, as energy expenditure during evening fast is less than at any other time. Yet, unlike certain flawed bodybuilding trainers may suggest, a bodybuilder is in great need of calories during sleep, as this is when the majority of muscle growth occurs. In fact, since the body has a lengthy uninterrupted rest to repair and grow lean muscle mass, sufficient protein and calories must be present in order to maximize such progress, which is why a bedtime meal becomes critical. When nutrients are withheld prior to a lengthy rest period, although muscles wish to grow during such hours, they are unable to do so, and if an individual is using a lower calorie diet for fat reduction, many times muscle mass will even drop dramatically.

During fat loss periods, one of the most challenging obstacles for many bodybuilders is muscle maintenance, and making dramatic changes to a diet, whether it be reducing food intake below the maximum necessary for fat loss due to impatience, or eliminating food later in the evening, will greatly enhance the chance for muscle loss, which further suppresses metabolism, making future fat loss a chore. Unbeknownst to many, a properly structured bedtime meal can actually aid in fat reduction, as metabolism is stimulated due to a frequent meal structure, and avoiding food for extended periods can cause the body to restrict calorie burn. This can occur not only when decreasing frequency of meals during daylight hours, but also by skipping a moderately sized feeding prior to sleep. This is contradictory to the notion that food before bed increases the risk of fat increase or slows fat reduction, but far too many who integrate bedtime meals are using a larger quantity of food than is necessary to properly stimulate metabolism and sustain muscle mass, or are using excessive carbohydrates, as if the meal were preceding a weight lifting workout as opposed to a lengthy sleep session. A meal before sleep should be composed of mostly protein, as the body during rest craves primarily recovery and growth (by way of protein synthesis), but eliminating carbohydrates completely will cause the body to waste protein for energy, which reduces available nutrients for muscle recuperation, and places metabolism at risk.

Certain bodybuilders understand the importance of bedtime meals, and try to integrate several during the evening, waking up once or twice for extra food, believing this will aid muscle gain, but such a technique is harmful to overall progress, as consuming one properly designed bedtime meal is sufficient to promote muscle gains and proper metabolic stimulation, while waking up for another one or two meals will destroy proper sleep patterns, which are just as vital for muscle gains and proper metabolism as the meal itself. Waking up for extra food during time which should be devoted to rest prevents the body from utilizing calories properly, so for maximum muscle building and fat loss, aiming for a bedtime meal with controlled carbohydrate intake and sufficient protein once before a lengthy sleep is the most effective technique to aim for.