Healthy diet
A healthy diet is a diet that maintains or improves overall health. A healthy diet provides the body with essential nutrition: fluid, macronutrients such as protein, micronutrients such as vitamins, and adequate fibre and food energy.[2][3]
A healthy diet may contain fruits, vegetables, and whole grains, and may include little to no ultra-processed foods or sweetened beverages. The requirements for a healthy diet can be met from a variety of plant-based and animal-based foods, although additional sources of vitamin B12 are needed for those following a vegan diet.[4] Various nutrition guides are published by medical and governmental institutions to educate individuals on what they should be eating to be healthy. Nutrition facts labels are also mandatory in some countries to allow consumers to choose between foods based on the components relevant to health.[5][6]
Recommendations
World Health Organization
The World Health Organization (WHO) makes the following five recommendations with respect to both populations and individuals:[7]
Specific conditions
Diabetes
A healthy diet in combination with being active can help those with diabetes keep their blood sugar in check.[32] The US CDC advises individuals with diabetes to plan for regular, balanced meals and to include more nonstarchy vegetables, reduce added sugars and refined grains, and focus on whole foods instead of highly processed foods.[33] Generally, people with diabetes and those at risk are encouraged to increase their fiber intake.[34]
Hypertension
A low-sodium diet is beneficial for people with high blood pressure. A 2008 Cochrane review concluded that a long-term (more than four weeks) low-sodium diet lowers blood pressure, both in people with hypertension (high blood pressure) and in those with normal blood pressure.[35]
The DASH diet (Dietary Approaches to Stop Hypertension) is a diet promoted by the National Heart, Lung, and Blood Institute (part of the NIH, a United States government organization) to control hypertension. A major feature of the plan is limiting intake of sodium,[36] and the diet also generally encourages the consumption of nuts, whole grains, fish, poultry, fruits, and vegetables while lowering the consumption of red meats, sweets, and sugar. It is also "rich in potassium, magnesium, and calcium, as well as protein".
The Mediterranean diet, which includes limiting consumption of red meat and using olive oil in cooking, has also been shown to improve cardiovascular outcomes.[37]
Preliminary research indicated that a diet high in fruit and vegetables may decrease the risk of cardiovascular disease and death, but not cancer.[47] Eating a healthy diet and getting enough exercise can maintain body weight within the normal range and reduce the risk of obesity in most people.[48] A 2021 scientific review of evidence on diets for lowering the risk of atherosclerosis found that:[49]
Scientific research is also investigating impacts of nutrition on health- and lifespans beyond any specific range of diseases.
Research suggests that increasing adherence to Mediterranean diet patterns is associated with a reduction in total and cause-specific mortality, extending health- and lifespan.[50][51][52][53] Research is identifying the key beneficial components of the Mediterranean diet.[54][55] Studies suggest dietary changes are a factor of national relative rises in life-span.[56]
Approaches to develop optimal diets for health- and lifespan (or "longevity diets")[57] include:
Moreover, not only do the components of diets matter but the total caloric content and eating patterns may also impact health – dietary restriction such as caloric restriction is considered to be potentially healthy to include in eating patterns in various ways in terms of health- and lifespan.[65][66]
Other animals
Animals that are kept by humans also benefit from a healthy diet, but the requirements of such diets may be very different from the ideal human diet.[87]