Diet (nutrition)

Dietary choices

Exclusionary diets are diets with certain groups or specific types of food avoided, either due to health considerations or by choice. Many do not eat food from animal sources to varying degrees (e.g. flexitarianism, pescetarianism, vegetarianism, and veganism) for health reasons, issues surrounding morality, or to reduce their personal impact on the environment (e.g. environmental vegetarianism). People on a balanced vegetarian or vegan diet can obtain adequate nutrition, but may need to specifically focus on consuming specific nutrients, such as protein, iron, calcium, zinc, and vitamin B₁₂. Raw foodism and intuitive eating are other approaches to dietary choices. Education, income, local availability, and mental health are all major factors for dietary choices.

Weight management

A particular diet may be chosen to promote weight loss or weight gain. Changing a person's dietary intake, or "going on a diet", can change the energy balance, and increase or decrease the amount of fat stored by the body.

The terms "healthy diet" and "diet for weight management" (dieting) are often related, as the two promote healthy weight management. If a person is overweight or obese, changing to a diet and lifestyle that allows them to burn more calories than they consume may improve their overall health, possibly preventing diseases that are attributed in part to weight, including heart disease and diabetes. Within the past 10 years, obesity rates have increased by almost 10%. Conversely, if a person is underweight due to illness or malnutrition, they may change their diet to promote weight gain. Intentional changes in weight, though often beneficial, can be potentially harmful to the body if they occur too rapidly. Unintentional rapid weight change can be caused by the body's reaction to some medications, or may be a sign of major medical problems including thyroid issues and cancer among other diseases.

Meat consumption

Meat commonly refers to red meat from pork, beef, and lamb and to white meat from chicken and turkey. In Western countries, red meat is a significant source of energy and several nutrients such as protein, vitamins, minerals, and fatty acids. Meat can be processed by adding chemical preservatives, smoking, curing, salting, fermenting or canning.

According to the International Agency for Research on Cancer (IARC), processed meat causes cancer, particularly colorectal cancer, and all red meat is a "probable" cause of cancer. Strong evidence also links processed meat with higher risks of cardiovascular disease and type 2 diabetes. The World Cancer Research Fund recommends limiting red meat to no more than three servings per week and minimizing consumption of processed meats.

Environmental dietary choices

Agriculture is a driver of environmental degradation, such as biodiversity loss, climate change, desertification, soil degradation and pollution. The food system as a whole – including refrigeration, food processing, packaging, and transport – accounts for around one-quarter of greenhouse gas emissions. More sustainable dietary choices can be made to reduce the impact of the food system on the environment. These choices may involve reducing consumption of meat and dairy products and instead eating more plant-based foods, and eating foods grown through sustainable farming practices.

Religious and cultural dietary choices

Some cultures and religions have restrictions concerning what foods are acceptable in their diet. For example, only Kosher foods are permitted in Judaism, and Halal foods in Islam. Although Buddhists are generally vegetarians, the practice varies and meat-eating may be permitted depending on the sects. In Hinduism, vegetarianism is the ideal. Jains are strictly vegetarian and in addition to that the consumption of any roots (e.g., potatoes, carrots) is not permitted.

In Christianity there is no restriction on the kinds of animals that can be eaten, though various groups within Christianity have practiced specific dietary restrictions for various reasons. The most common diets consumed by Christians are the Mediterranean diet and vegetarianism. Mediterranean and vegetarian dietary patterns are often linked with balanced nutrition and better health outcomes.

Diet classification table