Diet types: An individual’s diet is the sum of food and drink that he or she habitually consumes. Dieting is the practice of attempting to achieve or maintain a certain weight through diet. People’s dietary choices are often affected by a variety of factors, including ethical and religious beliefs, clinical need, or a desire to control weight.
Not all diets are considered healthy. Some people follow unhealthy diets through habit, rather than through a conscious choice to eat unhealthily. Terms applied to such eating habits include “junk food diet” and “Western diet”. Many diets are considered by clinicians to pose significant health risks and minimal long-term benefit. This is particularly true of “crash” or “fad” diets–short-term, weight-loss plans that involve drastic changes to a person’s normal eating habits.
Diet Types: Vegetarian diets
A vegetarian diet is one which excludes meat. Vegetarians also avoid food containing by-products of animal slaughter, such as animal-derived rennet and gelatin.
- Fruitarian diet: A diet which predominantly consists of raw fruit.
- Lacto vegetarianism: A vegetarian diet that includes certain types of dairy, but excludes eggs and foods which contain animal rennet. A common diet among followers of several religions, including Hinduism, Sikhism and Jainism, based on the principle of Ahimsa (non-harming).
- Ovo vegetarianism: A vegetarian diet that includes eggs, but excludes dairy.
- Ovo-lacto vegetarianism: A vegetarian diet that includes eggs and dairy.
- Vegan diet: In addition to the abstentions of a vegetarian diet, vegans do not use any product produced by animals, such as eggs, dairy products, or honey. The vegan philosophy and lifestyle is broader than just the diet and also includes abstaining from using any products tested on animals and often campaigning for animal rights.
Diet Types: Semi-vegetarian diets
- Semi-vegetarianism: A predominantly vegetarian diet, in which meat is occasionally consumed.
- Kangatarian: A diet originating from Australia. In addition to foods permissible in a vegetarian diet, kangaroo meat is also consumed.
- Pescetarian diet: A diet which includes fish but not other meats.
- Plant-based diet: A broad term to describe diets in which animal products do not form a large proportion of the diet. Under some definitions a plant-based diet is fully vegetarian; under others it is possible to follow a plant-based diet whilst occasionally consuming meat.
- Pollotarian: Someone who eats chicken or other poultry, but not meat from mammals, often for environmental, health or food justice reasons.
- Pollo-pescetarian: Someone who eats both poultry and fish/seafood, though no meat from mammals.
Diet Types: Weight control diets
Many of the diets listed below could fall into more than one subcategory. Where this is the case, it is noted in that diet’s entry.
- 5:2 diet: an intermittent fasting diet popularized by Michael Mosley in 2012.
- Intermittent fasting: Cycling between non-fasting and fasting as a method of calorie restriction.
- Body for Life: A calorie-control diet, promoted as part of the 12-week Body for Life program.
- Cookie diet: A calorie control diet in which low-fat cookies are eaten to quell hunger, often in place of a meal.
- Nutrisystem diet: The dietary element of the weight-loss plan from Nutrisystem, Inc. Nutrisystem distributes low-calorie meals, with specific ratios of fats, proteins and carbohydrates.
- Weight Watchers diet: Foods are assigned point values; dieters can eat any food with a point value provided they stay within their daily point limit.
Very low calorie diets
A very low calorie diet is consuming fewer than 800 calories per day. Such diets are normally followed under the supervision of a doctor. Zero-calorie diets are also included.
- Inedia (breatharian diet): A diet in which no food is consumed, based on the belief that food is not necessary for human subsistence.
- KE diet: A diet in which an individual feeds through a feeding tube and does not eat anything.
- Atkins diet: A low-carbohydrate diet, popularized by nutritionist Robert Atkins in the late-20th and early-21st centuries. Proponents argue that this approach is a more successful way of losing weight than low-calorie diets; critics argue that a low-carb approach poses increased health risks. The Atkins diet consists of four phases (Induction, Balancing, Fine-Tuning and Maintenance) with a gradual increase in consumption of carbohydrates as the person goes through the phases.
- Dukan Diet: A multi-step diet based on high protein and limited carbohydrate consumption. It starts with two steps intended to facilitate short term weight loss, followed by two steps intended to consolidate these losses and return to a more balanced long-term diet.
- Kimkins: A heavily promoted diet for weight loss, found to be fraudulent.
- South Beach Diet: Diet developed by the Miami-based cardiologist Arthur Agatston, M.D., who says that the key to losing weight quickly and getting healthy isn’t cutting all carbohydrates and fats from your diet, but choosing the right carbs and the right fats.
- Stillman diet: A carbohydrate-restricted diet that predates the Atkins diet, allowing consumption of specific food ingredients.
- McDougall’s starch diet is a high calorie, high fiber, low fat diet that is based on starches such as potatoes, rice, and beans which excludes all animal foods and added vegetable oils. John A. McDougall draws on historical observation of how many civilizations around the world throughout time have thrived on starch foods.
Diet Types: Crash diets
Crash diet and fad diet are general terms. They describe diet plans which involve making extreme, rapid changes to food consumption, but are also used as disparaging terms for common eating habits which are considered unhealthy. Both types of diet are often considered to pose health risks. Many of the diets listed here are weight-loss diets which would also fit into other sections of this list. Where this is the case, it will be noted in that diet’s entry.
- Beverly Hills Diet: An extreme diet which has only fruits in the first days, gradually increasing the selection of foods up to the sixth week.
- Cabbage soup diet: A low-calorie diet based on heavy consumption of cabbage soup. Considered a fad diet.
- Grapefruit diet: A fad diet, intended to facilitate weight loss, in which grapefruit is consumed in large quantities at meal times.
- Monotrophic diet: A diet that involves eating only one food item, or one type of food, for a period of time to achieve a desired weight reduction.
- Subway diet: A crash diet in which a person consumes Subway sandwiches in place of higher calorie fast foods. Made famous by former obese student Jared Fogle, who lost 245 pounds after replacing his meals with Subway sandwiches as part of an effort to lose weight.
- Western dietary pattern: A diet consisting of food which is most commonly consumed in developed countries. Examples include meat, white bread, milk and puddings. The name is a reference to the Western world.
Diet Types: Detox diets
Detox diets involve either not consuming or attempting to flush out substances that are considered unhelpful or harmful. Examples include restricting food consumption to foods without colorings or preservatives, taking supplements, or drinking large amounts of water. The latter practice in particular has drawn criticism, as drinking significantly more water than recommended levels can cause hyponatremia.
- Juice fasting: A form of detox diet, in which nutrition is obtained solely from fruit and vegetable juices. The health implications of such diets are disputed.
- Master Cleanse: A form of juice fasting.
Some people’s dietary choices are influenced by their religious, spiritual or philosophical beliefs.
- Buddhist diet: While Buddhism does not have specific dietary rules, some buddhists practice vegetarianism based on a strict interpretation of the first of the Five Precepts.
- Hindu and Jain diets: Followers of Hinduism and Jainism may follow lacto vegetarian diets (though most do not, as some Hindu festivals require meat to be eaten), based on the principle of ahimsa (non-harming).
- Islamic dietary laws: Muslims follow a diet consisting solely of food that is halal – permissible in Islam. The opposite of halal is haraam, food that is Islamically Impermissible. Haraam substances include alcohol, pork, and any meat from an animal which was not killed through the Islamic method of ritual slaughter (Dhabiha).
- I-tal: A set of principles which influences the diet of many members of the Rastafari movement. One principle is that natural foods should be consumed. Some Rastafarians interpret I-tal to advocate vegetarianism or veganism.
- Kosher diet: Food permissible under Kashrut, the set of Jewish dietary laws, is said to be Kosher. Some foods and food combinations are non-Kosher, and failure to prepare food in accordance with Kashrut can make otherwise permissible foods non-Kosher.
- Seventh-day Adventist: Seventh-day Adventists combine the Kosher rules of Judaism with prohibitions against alcohol and caffeinated beverages and an emphasis on whole foods. About half of Adventists are lacto-ovo-vegetarians.
- Word of Wisdom: The name of a section of the Doctrine and Covenants, a book of scripture accepted by members of The Church of Jesus Christ of Latter-day Saints. Dietary advice includes (1) wholesome plants “in the season thereof”, (2) eating meat sparingly and only “in times of winter, or of cold, or famine”, and (3) grain as the “staff of life”.
Diets followed for medical reasons
People’s dietary choices are sometimes affected by intolerance or allergy to certain types of food. There are also dietary patterns that might be recommended, prescribed or administered by medical professionals for people with specific medical needs.
- Diabetic diet: An umbrella term for diets recommended to people with diabetes
- DASH diet (Dietary Approaches to Stop Hypertension): A recommendation that those with high blood pressure consume large quantities of fruits, vegetables, whole-grains and low fat dairy foods as part of their diet, and avoid sugar sweetened foods, red meat and fats. Promoted by the US Department of Health and Human Services, a United States government organisation.
- Elemental diet: A medical, liquid-only diet, in which liquid nutrients are consumed for ease of ingestion.
- Elimination diet: A method of identifying foods which cause a person adverse effects, by process of elimination.
- Gluten-free diet: A diet which avoids the protein gluten, which is found in barley, rye and wheat. It is a medical treatment for gluten-related disorders, which include coeliac disease, non-celiac gluten sensitivity, gluten ataxia, dermatitis herpetiformis and wheat allergy.
- Gluten-free, casein-free diet: A gluten-free diet which also avoids casein, a protein commonly found in milk and cheese. This diet has been researched for efficacy in treatment of autism spectrum disorder.
- Healthy kidney diet: This diet is for those impacted with chronic kidney disease, those with only one kidney who have a kidney infection and those who may be suffering from some other kidney failure. This diet is not the dialysis diet, which is something completely different. The healthy kidney diet restricts large amounts of protein which are hard for the kidney to break down but especially limits: potassium and phosphorus-rich foods and beverages. Liquids are often restricted as well—not forbidden, just less of.
- Ketogenic diet: A high-fat, low-carb diet, in which dietary and body fat is converted into energy. It is used as a medical treatment for refractory epilepsy.
- Liquid diet: A diet in which only liquids are consumed. May be administered by clinicians for medical reasons, such as after a gastric bypass or to prevent death through starvation from a hunger strike.
- Low-FODMAP diet: A diet that consists in the global restriction of all fermentable carbohydrates (FODMAPs).
- Alkaline diet: The avoidance of relatively acidic foods – foods with low pH levels – such as grains, dairy, meat, sugar, alcohol, caffeine and fungi. Proponents believe such a diet may have health benefits; critics consider the arguments to have no scientific basis.
- Blood type diet: A diet based on a belief that people’s diets should reflect their blood types.
- Clean eating
- Eat-clean diet: Focusses on eating foods without preservatives, and on mixing lean proteins with complex carbohydrates.
- Fit for Life diet: Recommendations include not combining protein and carbohydrates, not drinking water at meal time, and avoiding dairy foods.
- Food combining diet: A nutritional approach where certain food types are deliberately consumed together or separately. For instance, some weight control diets suggest that proteins and carbohydrates should not be consumed in the same meal.
- Gerson therapy: A form of alternative medicine, the diet is low salt, low fat and vegetarian, and also involves taking specific supplements. It was developed by Max Gerson, who claimed the therapy could cure cancer and chronic, degenerative diseases. These claims have not been scientifically proven, and they can cause serious illness and death.
- The Graham Diet: A vegetarian diet which promotes whole-wheat flour and discourages the consumption of stimulants such as alcohol and caffeine. Developed by Sylvester Graham in the 19th century.
- Hay diet: A food-combining diet developed by William Howard Hay in the 1920s. Divides foods into separate groups, and suggests that proteins and carbohydrates should not be consumed in the same meal.
- High-protein diet: A diet in which high quantities of protein are consumed with the intention of building muscle. Not to be confused with low-carb diets, where the intention is to lose weight by restricting carbohydrates.
- High residue diet: A diet in which high quantities of dietary fiber are consumed. High-fiber foods include certain fruits, vegetables, nuts and grains.
- Inuit diet: Inuit people traditionally consume food that is fished, hunted or gathered locally; predominantly meat and fish.
- Jenny Craig: A weight-loss program from Jenny Craig, Inc. It includes weight counselling among other elements. The dietary aspect involves the consumption of pre-packaged food produced by the company.
- Locavore diet: a neologism describing the eating of food that is locally produced, and not moved long distances to market. An example of this was explored in the book 100-Mile Diet, in which the authors only consumed food grown within 100 miles of their residence for a year. People who follow this type of diet are sometimes known as locavores.
- Low carbon diet: Consuming food which has been produced, prepared and transported with a minimum of associated greenhouse gas emissions.
- Low-fat diet
- Low glycemic index diet
- Low-protein diet
- Low sodium diet
- Low-sulfur diet
- Macrobiotic diet: A diet in which processed food is avoided. Common components include grains, beans and vegetables.
- Mediterranean diet: A diet based on habits of some southern European countries. One of the more distinct features is that olive oil is used as the primary source of fat.
- MIND diet: combines the portions of the DASH diet and the Mediterranean diet. The diet is intended to reduce neurological deterioration such as Alzheimer’s disease.
- Montignac diet: A weight-loss diet characterised by consuming carbohydrates with a low glycemic index.
- Negative calorie diet: A claim by many weight-loss diets that some foods take more calories to digest than they provide, such as celery. The basis for this claim is disputed.
- Okinawa diet: A low-calorie diet based on the traditional eating habits of people from the Ryukyu Islands.
- Omnivore: An omnivore consumes both plant and animal-based food.
- Organic food diet: A diet consisting only of food which is organic – it has not been produced with modern inputs such as synthetic fertilizers, genetic modification, irradiation, or synthetic food additives.
- Paleolithic diet: Can refer either to the eating habits of humans during the Paleolithic era, or of modern dietary plans purporting to be based on these habits.
- Prison loaf: A meal replacement served in some United States prisons to inmates who are not trusted to use cutlery. Its composition varies between institutions and states, but as a replacement for standard food, it is intended to provide inmates with all their dietary needs.
- Pritikin Program for Diet and Exercise: A diet which focusses on the consumption of unprocessed food.
- Raw foodism: A diet which centres on the consumption of uncooked and unprocessed food. Often associated with a vegetarian diet, although some raw food dieters do consume raw meat.
- Scarsdale Medical Diet
- Shangri-La Diet
- Slimming World diet
- Slow-carb diet
- Smart For Life
- Sonoma diet: A diet based on portion control and centered around consuming “power foods”
- SparkPeople diet
- Sugar Busters!: Focuses on restricting the consumption of refined carbohydrates, particularly sugars.
- Tongue Patch Diet: Stitching a Marlex patch to the tongue to make eating painful.
- Zone diet: A diet in which a person attempts to split calorie intake from carbohydrates, proteins and fats in a 40:30:30 ratio.