To survive, humans and all other animals need food. For each day that you live, you eat more food than you can eat. If all food sources were exhausted, humans would die of starvation. To meet energy requirements we eat food, which consists of plant material, animal matter and fungi.
Food is any material consumed to supply body energy. Body energy is the energy required to perform all activities necessary for living. Food energy is either derived from the food itself or is used for making up for the loss of energy that the body uses from the food that it eats. The body uses all available food energy, stored as fat or stored in the muscles as energy, to build and repair tissue, particularly muscle tissue.
People differ in terms of their food energy requirements and these needs vary according to sex, age and physical activity. Some people require a greater amount of food energy than others, while lean meat is beneficial for all. Lean meat contains more nutrients than other meats and therefore is recommended as part of a vegetarian diet, where other meats are not preferred. Lean meat contains protein, iron, zinc, magnesium, phosphorus, potassium and vitamins A, B, C and E.
Carbohydrates are the main source of carbohydrates. Grains such as wheat, rice, oats and barley contain carbohydrates. Oats and rice are high in both soluble and insoluble fiber, as well as protein and calories. These foods are also high in B vitamins and minerals such as folic acid, thiamin, magnesium and iron. Most people do not require the level of supplementation that is required to maintain a healthy immune system.
The majority of food additives and preservatives are derived from carbohydrates. These food additives are called polysaccharides. Polysaccharides are made up of chains of single sugars or non-lactose sugars. A wide range of food additives, including artificial sweeteners and colorings, are broken down into either polysaccharides or glucose. Excessive amounts of glucose or sugar in the body can be detrimental to the body, as excess sugar or glucose is digested too quickly and leads to excess fat.
Foods contain nutrients that protect us against disease, infection and injury. For example, some foods contain antioxidants that attack free radicals, molecules that cause tissue damage and cause aging. Other nutrients protect the intestines and help maintain a healthy balance of intestinal bacteria. Food enzymes help in digestion and may even regulate the production and release of other nutrients such as energy.