Food is any substance consumed to provide energy, sustain life and promote growth. It is generally of plant or animal origin and contains essential nutrients such as carbohydrates, fats, proteins, vitamins and minerals. Food is obtained by eating and is absorbed through the digestive system. Different organisms have evolved distinct feeding behaviours that fit their metabolic needs and environmental conditions.
A healthy diet is balanced over a period of time and includes a variety of foods from the different food groups. It should be low in added sugars, sodium (salt) and unhealthy fats, and high in fiber. The diet should also be moderate in calories to maintain a healthy weight and reduce the risk of heart disease, stroke, cancer and diabetes.
The dietary requirements of humans and other animals vary according to their species, age, gender, activity level and physiological state. For example, infants and young children require a higher intake of calories and nutrients than adults. Healthy eating patterns should be established early in life to ensure an adequate supply of essential nutrients.
Unprocessed and minimally processed foods are rich in vitamins and minerals. They include the natural edible parts of plants and animals as well as whole grains, fruits, vegetables, nuts and seeds. These foods are generally high in fibre, which is good for digestion and bowel health. They also contain healthy monounsaturated and polyunsaturated fats and are low in saturated fat.
Processed foods have been altered from their natural state for purposes such as convenience, preservation and safety. The processes involved in processing include washing, cleaning, milling, heating, canning, freezing and dehydration. The addition of flavours, colours and nutrients may also occur during processing. Processed foods are usually high in salt, sugar and unhealthy fats. Examples of processed foods are packaged snacks, frozen dinners and ready-made baked goods.
Modern technology has transformed the way people produce and consume food. Advances in refrigeration and transportation have allowed larger quantities of food to be produced and stored for longer periods of time. Modern industrial techniques for cooking and preparation of food have contributed to the increased availability of fast food, which is often high in fats, salt and added sugars.
A healthy diet is one that consists of mostly unprocessed or minimally processed foods, such as fruits, vegetables, whole grains, low-fat dairy and lean meats. It is also important to consume sufficient amounts of water and avoid excessive consumption of alcohol and sugary beverages, which are high in calories. The health of an individual is closely linked to the nutritional quality and safety of the food they eat. Poor dietary choices can lead to obesity, which is a major contributor to chronic diseases such as cardiovascular disease and diabetes. On the other hand, an optimally nutritious diet can contribute to mental health by promoting cognitive function and reducing the risk of neurodegenerative diseases.