Food Composition

Food is everything we eat. It provides the energy and nutrients needed to support all body functions, maintain good health and carry out everyday activities. Food contains many ingredients, called nutrients, which help the body function well. Foods are complex mixtures of different components, providing varying amounts of the nutrients the body needs. Most nutrients cannot be produced by the body and must be taken in adequate amounts from the food we eat in order to be healthy and prevent disease. No single food contains all the nutrients needed by the body in the right amounts; one food may be rich in one or two nutrients, but low in other essential nutrients. It is only by eating adequate amounts of a variety of foods that we can help ensure that we will take in the right amounts of the nutrients needed for good health and nutritional status.

The nutrients in foods are grouped by their similar characteristics and the functions that they carry out in the body. Certain nutrients are called “macro” nutrients because the body needs them in fairly large amounts in order to function properly; these are carbohydrates, protein and fats. Other nutrients, also necessary for body functions, are called “micro” nutrients because the body needs them in very small amounts; these are vitamins and minerals. A nutrient can perform one or several functions in the body.

The three macronutrients – carbohydrates, protein and fats – are the major source of energy and bulk (volume) in our diets. They are the only nutrients that contain energy from food, which is measured in calories. Energy in our food is necessary for activity, growth and other body functions such as thinking, digesting and metabolizing food (all reactions of the body to use food), breathing, and circulating blood and oxygen. Getting sufficient energy is essential for everyone in order to maintain body growth and development and good health. Energy is so important to survival that we have developed the ability to store it for future use in the form of fat if we take in more than we need at the moment. Carbohydrates, protein and fats, in addition to providing energy, each have very specific functions in the body and must be supplied in sufficient amounts to carry out those functions.