dieting is the practice of eating food in a regulated and supervised fashion to decrease, maintain, or increase body weight, or to prevent and treat diseases, such as diabetes and obesity. a restricted diet is more often pursued by those wanting to lose weight. continuous dieting is recommended by us guidelines for obese or diabetic individuals to reduce body weight and improve general health. some people follow a diet to gain weight (usually in the form of muscle). diets can also be used to maintain a stable body weight and improve health.
several diets to promote weight loss have been devised: low-fat, low-carbohydrate, low-calorie, very low calorie and more recently flexible dieting. 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. at two years, all calorie-reduced diet types cause equal weight loss irrespective of the macro nutrients emphasized. in general, the most effective diet is any which reduces calorie consumption. several diets are effective for weight loss of obese individuals with similar results, diet success being most predicted by adherence with little effect of the type or brand of diet. dieting appears more effective than exercise for weight loss, but combining both provides even greater long-term results.
short-term dieting result 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.
the first popular diet was "banting", named after william banting. in his 1863 pamphlet, letter on corpulence, addressed to the public, he outlined the details of a particular low-carbohydrate, low-calorie diet that had led to his own dramatic weight loss.