Lean bulking, also known as clean bulking, is a method of bulking that aims to increase lean body mass while minimizing added body fat. The goal of lean bulking is to add muscle while minimizing fat gain, which can be achieved through a specialized, targeted diet. Unlike dirty bulking, which involves cramming your diet with high-calorie foods that are traditionally thought to be unhealthy in order to gain weight quickly, lean bulking involves regulating the number of calories and the type of foods you eat so that the majority of the weight you gain is muscle, not fat. The main disadvantage of lean bulking is that it requires precision, as there is a smaller calorie surplus, giving you a smaller margin for error. However, lean bulking is often utilized by athletes who desire to stay relatively lean in the off-season, such as mixed martial arts fighters, boxers, gymnasts, strength athletes, and physique athletes.