In the study of nutrition, food is defined as all the substances available to a living being to feed on so that their physiological processes can be carried out normally. Food is defined as any material used to give nourishment to the organisms. Food is generally of animal, plant or bacterial source, and includes essential nutrients, including proteins, vitamins, sugars, or other macro nutrients. The food that we eat can be categorized into three main types: animal food, plant food and microbial food. Animal food refers to all the foods that are derived from animals such as milk, eggs and meat; plant food refers to all foods that are derived from plants such as vegetables, fruits, legumes and grains; and microbiological food is food that is obtained by ingestion or cultivating of microorganisms.
Animal foods are grouped into four broad categories: animal fats, oils and spreads, dairy products, and grains. The animal proteins are mainly used in proteins – sources of building blocks of protein and skin; fats are used for the production of many other food products, especially those with a high content of calories; and dairy products include cheese, butter, ice cream and yogurt. The grains, such as millet, sorghum, flax seeds, and other kinds of semolina, are used as staples by most of the African communities. They form the basis of a healthy balanced diet, which is known as the “golden standard” by many scholars.
Animal fat is mainly composed of trioleic acid, which is a fatty acid having a hydrogen atom and a sulfur nucleus. The most commonly consumed animal fat is the saturated fat (or saturated fatty acids) that may also contain varying amounts of phospholipids, and several compounds that may result in free radicals. Saturated fat is the principal component of soft fat, which is the major component of human body fat. The consumption of fat may affect nutrition in two ways. One way it may increase blood cholesterol level, which may result in a heart disease; and another way it may decrease the process of fat metabolism, reducing the rate of fat utilization and increasing body weight.
The fat that is derived from poultry or other animal source contains the following fatty acids: oleic acid, stearic acid, palmitic acid, and iduronic acid. Animal meat is also rich in vitamins A, B-complex, C, D, and E. These vitamins are called essential fatty acids, since they are needed to build cell membrane, tissue, organs, and so on. Several vegetables contain a group of vitamins and minerals called carotenoids. These include beta carotene, lycopene, and several other forms of carotenoids. Lycopene is the most abundant pigment in red fruits and vegetables and may contribute to cancer prevention.
Animal fats and oils are characterized by the chemical substance called omega-3 fatty acids. There are two categories of fats: phosphate and arginine-o-phosphate. Phosphate fats are easier to digest than arginine-o-phosphate fats. It is therefore believed that the fats are more healthful than non-animal fats and oils.
Vegetables, fruits, legumes, grains, nuts, seeds, and oils all contain many essential nutrients. Some of these nutrients are fat-soluble, meaning that they are separated from the body and need to be taken with food. Examples of fat soluble nutrients are vitamins A, B-complex, C, D, and E, calcium, magnesium, potassium, phosphorus, potassium, sodium, and zinc. All foods and drinks should contain the vitamins, minerals, and nutrients that are listed here.