The human movement system must be properly nourished in order to reach the fitness goals desired. Therefore it is very important to understand basic nutrition concept. Nutrition is defined as the process by which and animals consume food for growth and tissue repair. The size of the animal or plant is determined by calorie intake vs expenditure. Nutrition also includes hydration due to the fact that the body is approximately 60% water. A general rule of thumb for hydrating is to consume about 1 gallon of water per day.