When considering the diet and nutrition intake for an endurance athlete there are two main priorities. The first is consuming proper fluids and the second is consuming adequate calories and macronutrients.
Endurance athletes who train multiple times a day are at high risk for dehydration considering the fluid loss through sweat from intense and lengthy exercise bouts. Water and electrolytes in the body’s system are essential for proper digestive, brain, and muscular function.
Macronutrient distributions are not one size fits all for everybody or every part of an athletic season. However, experts suggest between 7-12 g/kg (of body weight) of carbohydrates per day for endurance athletes. If training on the lower end of the spectrum closer to one hour a day, 7 g/kg will suffice. If training between four and six hours a day, an athlete will need to consume 10-12k/kg per day.
The rest of a diet should consist of a range from 1.2-1.4 g/kg of protein and 1 g/kg of fats per day. These macronutrient distributions combined with adequate fluids and electrolytes will keep the body replenished and capable of training.