Diet is the sum of the food consumed by a body. Proper nutrition for a human requires vitamins, minerals, proteins, and fuel in the form of carbohydrates and fats. Imbalances between the consumed fuels and expended energy results in either starvation or excessive reserves of adipose tissue, or body fat.

Physical fitness is a result of regular physical activity, proper diet and nutrition, and proper rest for physical recovery within the parameters allowed by the genome.