Why is nutrition important for swimmers? A swimmer that is training heavily (more than two hours a day) should eat four to seven meals (3 major + 4 small) a day. The amount of endurance it takes to be a good swimmer is why a swimmer's nutrition is so crucial to their strength and speed in the water. It takes a good three hours for your body to actually digest the food you’re eating, particularly all major meals, so if the swimmer has eaten an hour before he/she hits the pool,