A food is a substance that provides energy and nutrition for living things. It is usually of plant or animal origin, but can also be mineral or chemical. People eat food to meet their nutritional needs, but they also use it as a source of pleasure or comfort. Humans are omnivorous, eating both plants and animals for food.
Foods can be eaten raw or cooked, and they are preserved by refrigeration, freezing, drying, salting, smoking, or pickling. Cooking makes foods more digestible and changes their physico-chemical properties. People also add flavors to food through cooking and processing, and they may add vitamins and minerals to food to improve its nutritional value.
The most important food groups for a healthy diet are vegetables, fruits, lean meats and grains. A person should eat foods from each group at least three times a day.
In addition, the body needs healthy fats and protein for energy and to repair and replace cells and tissues. These nutrients can be found in fish, shellfish, nuts and seeds, whole grains, low-fat dairy products, and vegetable oils.
Eating a balanced diet can help keep weight under control and reduce the risk of heart disease, high blood pressure, diabetes and cancer. It can also improve mental health, especially in children.
A good diet can also fuel a child’s brain, making them more likely to concentrate and perform well at school. Foods that are particularly good for the brain include fatty fish, like salmon; eggs (for the memory-supporting choline); peanut butter or almond butter, which contain vitamin E; and leafy green vegetables, such as kale, broccoli and spinach.
Diets vary greatly from country to country, and even within a country, climate and tradition can affect what people eat. For example, in colder regions with short growing seasons, people rely more on root crops such as potatoes and carrots than in warmer areas with longer growing seasons, where fruit is a staple. Immigrants also bring new ideas about food to their adopted homes, and many dishes associated with national cuisines feature ingredients not native to the country. For example, chicken tikka masala was invented in Glasgow by Pakistani immigrants.
A person can save time and money by preparing meals from scratch, but sometimes it is necessary to rely on processed foods. When this happens, it is important to choose items that are low in sodium, added sugars and saturated fats. Processed foods should be consumed sparingly, as they can contribute to overeating and obesity. It is also helpful to eat with others, as this can help people recognize when they are full. Finally, it is important to eat slowly and chew foods thoroughly. This allows the brain to signal when a person is full, and it also helps avoid overeating.