Food is any substance eaten by living organisms as part of their metabolism to obtain energy and nourishment for growth, repair, and maintenance. It is usually of plant or animal origin, and contains essential nutrients such as carbohydrates, fats, proteins, vitamins, water, and minerals. Most people eat many different foods to get the nutrients they need to stay healthy. People also eat foods to enjoy the taste and other properties of the food. Some people like to eat foods that are culturally significant or have a religious significance.
The food available to humans has changed dramatically over time. Early humans were hunter-gatherers who ate whatever was available in their immediate environment. With the advent of agriculture and animal husbandry, food became more standardized. People started to grow their own crops and domesticate animals. They began to settle in one place and develop agricultural practices that made it possible to produce large quantities of a few types of foods.
Modern food science is a relatively new field that studies the interaction between food and human beings. It seeks to understand the processes by which food is grown, prepared, and consumed and the effects that these have on humans and on the environment. It incorporates aspects of chemistry, biology, mathematics, engineering, and psychology in the study of food.
A healthy diet is comprised of foods that are low in saturated and trans fats, added sugars, and sodium. It includes a variety of fruits, vegetables, whole grains, lean meats, fish, eggs, nuts and seeds. The dietary fiber in these foods helps to prevent constipation and indigestion, while the vitamins and minerals found in them help maintain good health. Adding herbs and spices to meals can add flavor while keeping calories low.
Almost all foods are processed in some way before they are eaten. This processing may involve cooking, grinding, heating, freezing, or canning. The major reasons for processing are to eliminate micro-organisms that cause disease, and to preserve the food longer. The nutrient content of foods can be affected by the type of processing they undergo, with water-soluble vitamins (such as vitamin C) being most susceptible to loss.
Whenever possible, it is best to choose unprocessed foods. This means eating a wide variety of fruits and vegetables, choosing those that are in season for the freshest flavor, and avoiding over-processed foods. Including a variety of foods in the diet is important because each food offers a unique combination of vitamins and minerals that can protect against certain diseases and promote general health. A person should try to eat at least the recommended number of servings of each food group each day.