Food is any material consumed by an organism to give it nutritional support in one of several ways. The word “food” in food refers to the substances most appropriate to the living organisms for their growth and maintenance. In plants, food is generally of vegetable, animal or even fungal type, and includes necessary nutrients, including vitamins, proteins, carbohydrates, and fats. In animals, food is generally of animal origin and has organs appropriate for digestion; fats are used for energy and some types of protein are the only source of essential amino acids.
Foods provide the bulk and energy needs of organisms and therefore provide sustenance, as well as being the main part of the diet, particularly in early life and through the process of evolution. Food is divided into three main categories: carbohydrates (including glucose, sucrose, dextrose, glucose monohydrate, lactose, maltose, rice, corn, pasta, flour), proteins (which include animal proteins and dairy products), and vitamins (which include A, B, C, D & E). A wide range of other nutrients is also available in various food materials. The major classes of nutrients are vitamins, minerals, trace elements, hormones, enzymes, food enzymes, and antimicrobials. The arrangement of carbohydrates, protein, vitamins and trace minerals on the food plant stems is well known, while the arrangement of hormones, enzymes, food enzymes and antimicrobials on the roots is less well understood.
It is important to consume a healthy diet that provides a balance of carbohydrates, proteins and vitamins in order to maintain a healthy body weight and contribute to health and longevity. The main objective of a healthy diet is to ensure adequate supplies of all the food groups and to maintain adequate physiological activity to enable the efficient use of the energy produced by the food. This means that the quantity of carbohydrates in the diet must be in sufficient proportion to enable the body to derive its daily needs from them, in a balanced way.
A healthy diet is incomplete without the food groups recognized by the food pyramid. These groups are fruits, vegetables, grains, legumes and nuts. The food pyramid enables us to evaluate our intake of food based on our food consumption and nutritional needs. According to this pyramid, 5% of the total calories needed for daily functioning is represented by the cereal group and another 5% by the vegetable group. In case one does not eat any of these, the intake of non-legume foods like potatoes or raw vegetables would have to be replaced by some vegetable or fruit substitute.
The next step in an individual’s food nutrition plan is to determine which of the food groups would provide the right sources of the nutrients required by the body. The first step in this process is determining the amount of the particular nutrient required by the body in a day. Based on this information, a dietary nutrient needs evaluation is performed and the appropriate food sources for each group are selected.
The nutritional value of the food source is primarily affected by the source of protein, carbohydrates, fat, and fiber. Animal products, including milk and meat, have much higher protein contents than plant foods, whereas plant foods, such as vegetables, have higher carbohydrate contents than animal products. Due to the wide range of food choices available today, the food pyramid can be used as a guide in determining dietary needs. Meats and eggs are included in animal products, whereas they are completely absent in plant foods.