Macronutrients

"The composition of macronutrients in the diet is a key factor in maximizing performance for athletes. Carbohydrates are an important fuel source for the brain and muscle during exercise. Carbohydrate storage in the liver and muscle cells are relatively limited and therefore it is important for athletes to consume enough carbohydrates from their diet. Carbohydrate needs should increase about 3-10 g/kg/day depending on the type of training or competition. Daily carbohydrate needs vary by activity level: light, low-intensity or skill-based activities require 3-5 g/kg of the athlete’s body weight per day; moderate exercise programs of about 1 hour per day require 5-7 g/kg per day; high endurance programs involving about 1-3 hours per day of moderate- to high-intensity exercise require 6-10 g/kg per day; and very high activity involving 4-5 hours per day of moderate- to high-intensity exercise requires 8-12 g/kg per day. Fat is a necessary component of a healthy diet to provide energy, essential fatty acids and to facilitate the absorption of fat-soluble vitamins. Athletes are recommended to consume the same amount of fat in the diet as the general population, 20-35% of their energy intake. Although these recommendations are in accordance with public health guidelines, athletes should individualize their needs based on their training level and body composition goals. Athletes who choose to excessively restrict their fat intake in an effort to lose body weight or improve body composition should ensure they are still getting the minimum recommended amount of fat. Fat intakes below 20% of energy intake will reduce the intake of fat-soluble vitamins and essential fatty acids, especially omega 3’s. Although protein accounts for only about 5% of energy expended, dietary protein is necessary to support metabolic reactions that generate ATP, and to help muscles with maintenance, growth, and repair. During exercise, these metabolic reactions for generating ATP rely heavily on proteins such as enzymes and transport proteins. It is recommended that athletes consume 1.2 to 2.0 g/kg/day of proteins in order to support these functions. Higher intakes may also be needed for short periods of intense training or when reducing energy intake. Protein intake recommendations include 0.8 g/kg body weight for most adults, 1.2 to 1.4 for endurance athletes, 1.3 to 1.5 for vegetarian endurance athletes, 1.6 to 1.7 for strength athletes, and 1.7 to 1.8 for vegetarian strength athletes. It is important to consume adequate amounts of protein and to understand that the quality of the protein consumed affects the amount needed. High protein foods such as meats, dairy, and eggs contain all of the essential amino acids in relative amounts that most efficiently meet the body’s needs for growth, maintenance and repair of muscles. Vegetarian diets contain protein that has lower digestibility and amino acid patterns that do not match human needs as closely as most animal proteins. To compensate for this as well as the fact that plant food protein sources also contain higher amounts of fiber, higher protein intakes are recommended for vegetarian athletes."