To gain muscle mass effectively, a positive energy balance of at least 2000-4000 kilojoules per day is required. This calls for a general increase in dietary intake. However, carbohydrate is the first nutrient to focus on, since muscle must be fuelled to do the training to stimulate muscles to grow. It is also important for athletes trying to gain muscle mass to meet their increased protein needs, but huge protein intakes are not required. In most cases, a high-energy diet that provides 1.2-2g of protein per kilogram of body mass will ensure that protein needs are met. These protein intakes are easily met by consuming a varied diet that meets your energy needs. Consuming protein above this level does not have an anabolic effect. Excess protein will be oxidised as an energy source and may contribute to gains in body fat. Very high protein diets displace other important nutrients from the diet and can be a source of saturated fat. Although it is important to achieve energy needs, a high-energy diet should not be seen as an excuse for gluttony. Excess consumption of high-fat foods can lead to excessive energy intake, and a greater risk of gaining fat mass rather than muscle.