Effectiveness




Several diets are effective for weight loss of obese individuals, with diet success most predicted by adherence and little effect resulting from the type or brand of diet. As weight maintenance depends on calorie intake, diets emphasising certain macronutrients (low-fat, low-carbohydrate, etc.) have been shown to be no more effective than one another and no more effective than diets that maintain a typical mix of foods with smaller portions and perhaps some substitutions (e.g. low-fat milk, or less salad dressing). A meta-analysis of six randomized controlled trials found no difference between low-calorie, low-carbohydrate, and low-fat diets, with a 2–4 kilogram weight loss over 12–18 months in all studies. Extreme diets may, in some cases, lead to malnutrition.

A major challenge regarding weight loss and dieting relates to compliance. While dieting can effectively promote weight loss in the short term, the intervention is hard to maintain over time and suppresses skeletal muscle thermogenesis. Suppressed thermogenesis accelerates weight regain once the diet stops, unless that phase is accompanied by a well-timed exercise intervention, as described by the Summermatter cycle. As a result of this, some argue against using weight loss as a goal, preferring other measures of health such as improvements in cardiovascular biomarkers, sometimes called a Health at Every Size (HAES) approach.

Short-term dieting results on average in a meaningful long-term weight-loss, although more limited because of gradual 1 to 2 kg/year weight regain. For each individual, the result will be different, with some even regaining more weight than they lost, while a few others achieve a tremendous loss, so that the "average weight loss" of a diet is not indicative of the results other dieters may achieve. A 2001 meta-analysis of 29 American studies found that participants of structured weight-loss programs maintained an average of 23% (3kg) of their initial weight loss after five years, representing an sustained 3.2% reduction in body mass.

Dieting appears more effective than exercise for weight loss, but combining both provides even greater long-term results.

Adverse effectsedit

A number of studies have found that intentional weight loss is associated with an increase in mortality in people without weight-related health problems. A 2009 meta-analysis of 26 studies found that "intentional weight loss had a small benefit for individuals classified as unhealthy (with obesity-related risk factors), especially unhealthy obese, but appeared to be associated with slightly increased mortality for healthy individuals, and for those who were overweight but not obese."

Eating disordersedit

In an editorial for Psychological Medicine, George Hsu concludes that dieting is likely to lead to the development of an eating disorder in the presence of certain risk factors. A 2006 study found that dieting and unhealthy weight-control behaviors were predictive of obesity and eating disorders five years later, with the authors recommending a "shift away from dieting and drastic weight-control measures toward the long-term implementation of heathful eating and physical activity".

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Types

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