Dieting is the practice of eating food in a regulated fashion to achieve or maintain a controlled weight. In most cases dieting is used in combination with physical exercise to Lose Weight in those who are overweight or obese. Some athletes, however, follow a diet to gain weight (usually in the form of muscle). Diets can also be used to maintain a stable body weight.
Diet to promote Weight Loss are generally divided into four categories: low-fat, low-carbohydrate, low-calorie, and very low calorie. A meta-analysis of six randomized controlled trials found no difference between the main diet types (low calorie, low carbohydrate, and low fat), with a 2–4 kilogram weight loss in all studies. At two years, all calorie-reduced diet types cause equal weight loss irrespective of the macronutrients emphasized.
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.
Diet And Dieting Types Of
Low-fat diets involve the reduction of the percentage of fat in one's diet. Calorie consumption is reduced because less fat is consumed. Diets of this type include NCEP Step I and II. A meta-analysis of 16 trials of 2–12 months' duration found that low-fat diets (without intentional restriction of caloric intake) resulted in average weight loss of 3.2 kg (7.1 lb) over habitual eating.
Low carbohydrate diets such as Atkins and Protein Power are relatively high in protein. Low-carbohydrate diets are sometimes ketogenic (i.e. they restrict carbohydrate intake sufficiently to cause ketosis).
Low-calorie diets usually produce an energy deficit of 500–1,000 calories per day, which can result in a 0.5 kilogram (1.1 lb) to 1 kilogram (2.2 lb) weight loss per week. Amongst some of the most commonly used low-calorie diets include DASH diet, Diet to Go, and Weight Watchers. The National Institutes of Health reviewed 34 randomized controlled trials to determine the effectiveness of low-calorie diets. They found that these diets lowered total body mass by 8% in the short term, over 3–12 months.
Very low-calorie diets
Very low calorie diets provide 200–800 calories per day, maintaining protein intake but limiting calories from both fat and carbohydrates. They subject the body to starvation and produce an average weekly weight loss of 1.5–2.5 kilograms (3.3–5.5 lb). "2-4-6-8", a popular diet of this variety, follows a four-day cycle in which only 200 calories are consumed the first day, 400 the second day, 600 the third day, 800 the fourth day, 1,000 the fifth day, and then the cycle repeats. These diets are not recommended for general use as they are associated with adverse side effects such as loss of lean muscle mass, increased risks of gout, and electrolyte imbalances. People attempting these diets must be monitored closely by a physician to prevent complications.
Each pound of body fat is maintained by less than one extra calorie per hour. In general, obesity is not a condition maintained by overeating; obesity is a condition brought about and maintained by eating more calories than the body uses, consistently. As a practical example, eating twenty-five hamburgers a year that are Burger King Whoppers rather than twenty-five McDonald Quarter Pounders can cause a weight gain of more than one and one-half pounds in that year. Twenty-five hamburgers represent 2% of yearly allotment of three meals a day. Making comparable choices at every meal for one year could yield an eighty-two-pound difference in body weight.
Detox diets claim to eliminate undesirable "toxins" from the human body rather than claiming to cause weight loss. Many of these use herbs and other homeopathic remedies, such as dandelion root (for liver filtering) and celery and other juicy low-calorie vegetables (for salt absorption).
Fat loss versus muscle loss
Weight loss typically involves the loss of fat, water and muscle. Overweight people, or people suffering from obesity, typically aim to reduce the percentage of body fat. Additionally, as muscle tissue is denser than fat, fat loss results in increased loss of body volume compared with muscle loss. Reducing even 10% body fat can therefore have a dramatic effect on a person's body shape. To determine the proportion of weight loss that is due to decreased fat tissue, various methods of measuring body fat percentage have been developed.
Muscle loss during weight loss can be restricted by regularly lifting weights (or doing push-ups and other strength-oriented calisthenics) and by maintaining sufficient protein intake. Those on low-carbohydrate diets, and those doing particularly strenuous exercise, may wish to increase their protein intake. According to the National Academy of Sciences, the Dietary Reference Intake for protein is 0.8 grams per kilogram of body weight for adults.
Diet and How the body eliminates fat
All body processes require energy in order to function properly. When the body is expending more energy than it is consuming (e.g. when exercising), the body's cells rely on internally stored energy sources, such as complex carbohydrates and fats, for energy.
The first source to which the body turns is glycogen (by glycogenolysis). Glycogen is a complex carbohydrate, 65% of which is stored in skeletal muscles and the remainder, in the liver (totaling about 2,000 kcal in the whole body). It is created from the excess of ingested macronutrients, mainly carbohydrates. When glycogen is nearly depleted, the body begins lipolysis, the mobilization and catabolism of fat stores for energy. In this process, fats, obtained from adipose tissue, or fat cells, are broken down into glycerol and fatty acids, which can be used to generate energy.
Diet food refers to any food or drink whose recipe has been altered in some way to make it part of a body modification diet. Although the usual intention is weight loss and change in body type, sometimes the intention is to aid in gaining weight or muscle as in bodybuilding supplements.
In addition to diet other words or phrases are used to identify and describe these foods including light or lite, lean, no calorie, low calorie, low fat, no fat, fat free, no sugar, sugar free, and zero calorie. In some areas use of these terms may be regulated by law. For example in the U.S. a product labeled low fat must not contain more than 3 grams of fat per serving; and to be labeled fat free it must contain less than 0.5 grams of fat per serving.
The process of making a diet version of a food usually requires finding an acceptable low calorie substitute for some high calorie ingredient. This can be as simple as replacing some or all of the food's sugar with a sugar substitute as is common with diet soft drinks such as Coca-Cola (for example Diet Coke). In some snacks, the food may be baked instead of fried thus reducing the calories. In other cases, low fat ingredients may be used as replacements.
In whole grain foods, the higher fiber content effectively displaces some of the starch component of the flour. Since certain fibers have no calories, this results in a modest caloric reduction. Another technique relies on the intentional addition of other reduced-calorie ingredients, such as resistant starch or dietary fiber, to replace part of the flour and achieve a more significant caloric reductionfor your diet.