The Importance of Food

Food is any substance ingested by organisms for the support of life and growth. It consists chiefly of carbohydrates, fats, proteins, and vitamins, minerals, or other substances that are absorbed and assimilated by living cells to provide energy, maintain vital processes, and stimulate growth. Plants and animals obtain most of their foods by eating other organisms or by obtaining them from the environment. The most common sources of human food are vegetables, fruits, grains, meats, eggs, and milk. Food is the source of energy for cellular metabolism and for physical activity.

Most people can easily afford to buy enough healthy foods to meet their calorie needs in developed countries, where malnutrition is not a major problem and most people live long lives. However, in some places the food supply is limited and many people have trouble getting access to affordable, nutritious foods. In addition, many people eat too much processed junk food that is high in calories, salt, and unhealthy fats.

Eating a variety of different foods is important for good health. Most adults need about five servings a day of each type of food. This means, for example, eating lots of fresh fruit and vegetables (try to eat a wide variety of colors), whole grains, beans or legumes, low-fat dairy products, and lean protein from fish, poultry, or nuts. It also means avoiding foods that are high in saturated or trans fats, and adding fiber to your diet.

The Food Guide Pyramid recommends limiting intake of sodium, or salt, and of sugary sodas and other sweet beverages. It also advises reducing fats and increasing the intake of unsaturated fats, which are healthier than saturated and trans fats. The pyramid also recommends limiting intake of red meat and consuming more poultry, fish, eggs, beans or legumes, and dairy products that are low in fat.

Processed foods are any food that has been changed from its natural state for storage, preparation, or sale. Examples include cooking, baking, freezing, canning, and frying. Processed foods usually have added nutrients and preservatives to improve taste, texture, or nutritional value.

Organic and natural foods are any food that has been grown or raised without chemicals. These foods are usually pricier than nonorganic or conventional foods, but may have less impact on the environment and human health.

A food chain is a sequence of organisms from plants and animals that transfer solar energy from producers to consumers in the form of food. Each level of the chain is a type of consumer, and each consumer extracts energy from the food at that trophic level. People can help to improve the world’s food supply by choosing to eat less animal products and more plants, thereby cutting out one step of the food chain, or reducing the number of steps in the chain. This will increase the amount of available energy at the final consumer level. Food chains can be shortened by allowing livestock to graze freely on pasture rather than in feedlots.