FoodFood | Definition & Nutrition | Britannica
                     Food | Definition & 
Nutrition | Britannica
food, substance consisting essentially of protein, carbohydrate, fat, and other nutrients 
used in the body of an organism to sustain growth and vital processes and to furnish 
energy. The absorption and utilization of food by the body is fundamental to nutrition 
and is facilitated by digestion. Plants, which convert solar energy to food by 
photosynthesis, are the primary food source. Animals that feed on plants often serve as 
sources of food for other animals. To learn more about the sequence of transfers of 
matter and energy in the form of food from organism to organism, see food chain. 
Hunting