Definition There is no single definition of what is a<unk> , encompassing a variety of diets with different approaches and evidence base, and thus different outcomes, advantages, and disadvantages. Furthermore, labeling a diet as a<unk>  is ever-changing, varying socially, culturally, timely, and subjectively. However, a common definition lies in the popularity of a diet promoting short-term changes instead of lifelong changes, and that popularity (or lack thereof) has no association with a diet's effectiveness, nutritional soundness, or safety. The Federal Trade Commission defines<unk> s as those that are highly restrictive and promoting energy dense foods that are often poor in nutrients. Types of<unk> s Although<unk> s are ever-changing, most can be categorized in these general groups: * Physical or physiological testing, such as applied kinesiology and blood group analysis * Low calorie diets: * Food-specific diets, which encourage eating large amounts of a single food, such as the Cabbage soup diet * High-protein, low-carbohydrate diets, such as the Atkins diet, which first became popular in the 1970s * High-fiber, low-calorie diets, which often prescribe double the normal amount of dietary fiber * Liquid diets, such as SlimFast meal replacement drinks * Fasting<unk> s are generally restrictive, and are characterized by promises of fast weight loss or great physical health (notably by "detoxification"), and which are not grounded in sound science. Some<unk> s, such as diets purporting to be alternative cancer treatments, promise health benefits other than weight loss. Commercial weight management organizations (CMWOs), such as Weight Watchers, were inappropriately associated with<unk> s in the past. Several factors can cause someone to start a<unk> , such as socio-cultural peer pressure on body image and self-esteem, including the effect of media, and economical cost of comprehensive programs.<unk> s Although not all<unk> s are inherently detrimental to health, there are "red flags" of<unk> ary advice, such as: * Promising rapid weight loss such as more than 1 kg/week (2 lb/week) or other extraordinary claims that are "too good to be true" * Being nutritionally imbalanced, or highly restrictive, forbidding entire food groups, or even only allowing one food or food type. In the most extreme form, they may claim that humans can survive without eating or by having liquid meals only or by consuming non-food items such as cotton wool * Recommending eating food in a specific order or combination, sometimes based on physiological properties such as genetics or blood type * Recommending specific foods purported to be detoxing or to "burn" fat * Promises a one-size-fits-all "magic bullet" with little to no effort, without including or encouraging long-term whole dietary changes nor physical exercise tailored to the specific needs of the individual * Based on anecdotal testimonials such as personal success stories, instead of medical evidence from randomized controlled trials * Requires the purchase of specific products, supplements, or resources * Provides no health warning for those with pre-existing medical illnesses * Focuses on appearance enhancement rather than health benefits * Being based on a "secret" that has yet to be discovered The National Institute for Health and Care Excellence in the United Kingdom devised a set of essential criteria to be met by commercial weight management organizations to be approved.
Fad diet
Plant-based diet
Rice diet
Atkins diet
Feingold diet
Western pattern diet
BRAT diet
Low-FODMAP diet