Physiological function of food: To provide energy

One of the functions of food is to provide energy. The body needs energy to sustain the involuntary processes essential for continuance of life, to carry out professional, household and recreational activities, to convert food into usable nutrients in the body, to grow and to keep warm. The energy needed is supplied by the oxidation of the foods consumed.

Food energy is defined as the energy released from carbohydrates, fats, proteins, and other organic compounds. Energy requirement depends on age, gender, body weight and activity level.

More than 20 food groups were principal food sources of energy. The two highest ranked food sources, yeast breads/rolls and cake/cookies/quick bread/pastry/pie, each provided 7.2% of total energy intake; soft drinks/soda (5.4%) was the third highest ranked food source.

Energy released by a particular food is a critical parameter in nutrition. Getting too much energy increases the risk of overweight and obesity, leading to increased risk of heart diseases, diabetes and certain types of cancer.

Fats have the greatest amount of food energy per mass, up to 9 kcal/g. Most of the carbohydrates and proteins have approximately 4 kcal/g, whereas fibers have less due to its low digestibility and absorbance in human bodies.
Physiological function of food: To provide energy