Food is any substance that can be eaten or drunk by living things to provide energy and nourishment. It contains the substances necessary for life, including carbohydrates, fats, proteins, vitamins, minerals and water. People require a mix of different foods to get the right balance of nutrients for good health.
Eating too much or too little of certain foods can cause illness or death. Some examples of foods are meat, fish, vegetables and fruits. People may eat food raw or cooked. Some foods are preserved by canning, freezing or drying. Food also can be enriched or fortified with added substances, such as iron and vitamin C.
Most people get their food from plants and animals. Plants are the source of vegetables, fruits and grains, which contain important vitamins, minerals and fiber. People who consume enough of these foods can live a long time. Animals, which are a source of meat and dairy products, are a richer source of protein, vitamins and minerals.
The composition of food has changed over the millennia, as people have moved to different places and learned how to farm and raise animals. The modern diet includes many processed foods, such as packaged snacks and frozen dinners, which are convenient but often high in salt, sugar and unhealthy fats.
Early humans were hunter-gatherers and ate whatever was available in their immediate environment. With the development of agriculture and animal husbandry, people began to live in one place for extended periods of time, changing their eating habits. People also discovered ways to preserve food for longer periods of time.
A person’s food choices depend on many factors, such as the availability of certain foods, cultural preferences and religion, economics and the environment. Some of these factors are controllable, such as selecting healthy foods. Other factors, such as climate and genetics, are beyond a person’s control.
Some of the functions of food include supplying energy, maintaining a stable body weight, preserving the integrity of cells and providing flavor. In addition, some foods have medical benefits. For example, folic acid in cereals helps prevent spina bifida, while fish oil can treat rheumatoid arthritis.
Food scientists study a wide range of topics, from the chemistry of flavors to the way food is preserved. They use this knowledge to create new foods or to make existing ones healthier. Food scientists are also concerned with the impact that food has on the environment, since growing, processing and transporting food uses up resources such as land, water and energy. They are working to develop ways of reducing the environmental impacts of food production and consumption. They are also investigating the possibility of using nanotechnology to improve food quality and safety.