The Atkins diet is based on the premise that people eat too many carbohydrates and this leads them to be overweight. There is only part truth to the preceding statement; if energy intake (rather than just carbohydrate intake) is more than energy expenditure you may become overweight.
The Atkins diet is a kind of low-carbohydrate fad diet.
The diet involves limited consumption of carbohydrates to switch the body’s metabolism from metabolizing glucose as energy over to converting stored body fat to energy. This process, called ketosis, begins when insulin levels are low; in normal humans, insulin is lowest when blood glucose levels are low (mostly before eating). Reduced insulin levels induce lipolysis, which consumes fat to produce ketone bodies. On the other hand, caloric carbohydrates (for example, glucose or starch, the latter made of chains of glucose) affect the body by increasing blood sugar after consumption.
In his early books such as Dr Atkins’ New Diet Revolution, Atkins made the controversial argument that the low-carbohydrate diet produces a metabolic advantage because “burning fat takes more calories so you expend more calories”. He cited one study in which he estimated this advantage to be 950 Calories (4.0 MJ) per day. A review study published in Lancet concluded that there was no such metabolic advantage and dieters were simply eating fewer calories due to boredom. Astrup stated, “The monotony and simplicity of the diet could inhibit appetite and food intake.”
In the most recent book by Westman, Phinney, and Volek, the authors suggest optimal levels of protein, fat, and calorie intake, and have moved away from the metabolic advantage theory.
The diet restricts “net carbs” (digestible carbohydrate grams that affect blood sugar less fiber grams). One effect is a tendency to decrease the onset of hunger, perhaps because of longer duration of digestion (fats and proteins take longer to digest than carbohydrates). The 2002 book New Diet Revolution states that hunger is the number one reason that low-fat diets fail, and that the diet is easier because one is satisfied with adequate protein, fat and fiber.