Atkins, is the most marketed and well-known of the low-carbohydrate diets. It was adapted by Dr. Robert Atkins in the 1960s from a diet he read in the Journal of the American Medical Association and utilized to resolve his own overweight condition following medical school and graduate medical training.
The Atkins Diet represents a departure from prevailing theories. Atkins claimed there are two main unrecognized factors about Western eating habits, arguing firstly that the main cause of obesity is eating refined carbohydrates, particularly sugar, flour, and high-fructose corn syrups; and secondly, that saturated fat is overrated as a nutritional problem, and that only trans fats from sources such as hydrogenated oils need to be avoided. Consequently, Dr. Atkins rejects the advice of the food pyramid, instead asserting that the tremendous increase in refined carbohydrates is responsible for the rise in metabolic disorders of the 20th century, and that the focus on the detrimental effects of dietary fat has actually contributed to the obesity problem by increasing the proportion of insulin-inducing foods in the diet.
While most of the emphasis in Atkins is on the diet, nutritional supplements and exercise are considered equally important elements.
Atkins involves the restriction of carbohydrates in order to switch the body's metabolism from burning glucose to burning protein and fat. This process (called lipolysis) begins when the body enters the state of ketosis as a consequence of running out of excess carbohydrates to burn. Dr. Atkins in his book New Diet Revolution claimed that the low-carb diet produces a "metabolic advantage" where the body burns more calories, overall, than on normal diets, and also expels some unused calories. He cited one study where he estimated this advantage to be 950 calories a day.
Atkins restricts "net carbs", or carbs that have an effect on blood sugar. Net carbohydrates can be calculated from a food source by subtracting sugar alcohols and fiber (which are shown to have a negligible effect on blood sugar levels) from total carbohydrates. Sugar alcohols need to be treated with caution, because while they may be slower to convert to glucose, they can be a significant source of glycemic load and can stall weight loss. Fructose (eg, as found in many industrial sweeteners) also contributes to caloric intake, though outside of the glucose-insulin control loop.
Preferred foods in all categories are whole, unprocessed foods with a low glycemic load.
Phases
There are four phases of the Atkins diet: induction, ongoing weight loss, pre-maintenance and lifetime maintenance.
Phase 1 : Induction
The Induction phase is the first, and most restrictive, phase of the Atkins Nutritional Approach. It is intended to cause the body to quickly enter a state of ketosis. Carbohydrate intake is limited to 20 net grams per day (grams of carbohydrates minus grams of fiber), 12 to 15 net grams of which must come in the form of salad greens and other vegetables. The allowed foods include a liberal amount of all meats, fish, shellfish, fowl, and eggs; up to 4 ounces of hard cheese; salad vegetables; other low carb vegetables; and butter and vegetable oils. Alcoholic beverages are not allowed during this phase. Caffeine is allowed in moderation so long as it does not cause cravings or low blood sugar. If a caffeine addiction is evident, it is best to not allow it until later phases of the diet. A daily multivitamin with minerals is also recommended.
The Induction Phase is usually when many see the most significant weight loss — reports of losses of 5 to 10 pounds per week are not uncommon when Induction is combined with daily exercise.
Atkins suggests the use of Ketostix, small chemically reactive strips used by diabetics. These let the dieter monitor when they enter the ketosis, or fat burning, phase.
However, simply watching your weight will work. Weight loss will vary by person, especially based on the amount needed to lose, but most people average approximately 10% of their total weight loss within the Induction period. Other indicators of ketosis include a metallic taste in the mouth, or bad breath.
Phase 2 : Ongoing weight loss
The Ongoing Weight Loss (OWL) phase of Atkins consists of an increase in carbohydrate intake, but remaining at levels where weight loss occurs. The target daily carbohydrate intake increases each week by 5 net grams. A goal in OWL is to find the "Critical Carbohydrate Level for Losing" and to learn in a controlled manner how food groups in increasing glycemic levels and foods within that group affect your craving control. The OWL phase lasts until weight is within 10 pounds (4.5 kg) of the target weight. At first weeks you should add more of the induction acceptable vegetables to your daily products. For example, 6-8 stalks of asparagus, salad, one cup of cauliflower or one half of avocado. The next week you should follow the carbohydrate ladder Dr Atkins created for this phase and add fresh dairy. The ladder has 9 rungs and should be added in order given. One can skip a rung if one does not intend to include that food group in one's permanent way of eating such as the alcohol rung.
The rungs are as follows:
- Induction acceptable vegetables
- Fresh dairy
- Nuts
- Berries
- Alcohol
- Legumes
- Other fruits
- Starchy vegetables
- Grains
Phase 3 : Pre-maintenance
Carbohydrate intake is increased again this time by 10 net carbs a week from the ladder groupings, and the key goal in this phase is to find the "Critical Carbohydrate Level for Maintenance", this is the maximum number of carbohydrates you can eat each day without gaining weight. This may well be above the level of carbohydrates inducing ketosis on a testing stick. As a result, it is not necessary to maintain a positive ketosis test long term.
Phase 4 : Lifetime maintenance
This phase is intended to carry on the habits acquired in the previous phases, and avoid the common end-of-diet mindset that can return people to their previous habits and previous weight. Whole, unprocessed food choices are emphasized, with the option to drop back to an earlier phase if you begin to gain weight.