Low-Carbohydrate Diets
Many promoters of dietary schemes would have us believe that a special substance or combination of foods will automatically result in weight reduction. That’s simply not true. To lose weight, you must eat less, or exercise more, or do both.

There are about 3,500 calories in a pound of body weight. To lose one pound a week, you must consume about 500 fewer calories per day than you metabolize. Most fad diets, if followed closely, will result in weight loss—as a result of caloric restriction. But they are usually too monotonous and are sometimes too dangerous for long-term use. Moreover, dieters who fail to adopt better exercise and eating habits will regain the lost weight—and possibly more. My advice to people who are considering a low-carbohydrate diet is not to try it on their own by reading a book but to seek supervision from a physician who can monitor what they do.

The most drastic way to reduce caloric intake is to stop eating completely. After a few days, body fats and proteins are metabolized to produce energy. The fats are broken down into fatty acids that can be used as fuel. In the absence of adequate carbohydrate, the fatty acids may be incompletely metabolized, yielding ketone bodies and thus ketosis. Prolonged fasting is unsafe, because it causes the body to begin to digest proteins from its muscles, heart, and other internal organs.

Low-carbohydrate diets also produce ketosis, but if properly designed, they enable the body’s nutritional needs to be met by dietary protein, dietary fat, stored body fat, and stored glycogen, so that body muscles are spared [1]. As this “nutritional ketosis” begins, there is a diuretic (water loss) effect, leading the dieter to think that significant weight reduction is taking place. However, most of the early loss is water rather than fat; the lost water is regained quickly when if the dieter resumes eating carbohyrate (as would occur, for example, with a balanced diet). Appetite, often reduced during ketosis, also returns when a balanced diet is resumed. In the past, it was thought that patients restricted their caloric intake because the food restrictions made the low-carbohydrate diet monotonous. However, current theorists suggest that appetite reduction has a hormonal basis [2].

The most widely publicized low-carbohydrate diet has been the one advocated by the late Robert C. Atkins, M.D., of New York City. His 1972 book Dr. Atkins’ Diet Revolution sold millions of copies within the first two years. His 1992 update, Dr. Atkins’ New Diet Revolution, has sold even more. The current plan has four steps: a 2-week “induction” period, during which the goal is to reduce carbohydrate intake to under 20 grams per day, and three periods during which carbohydrate intake is progressively raised but kept below what Atkins called “your critical carbohydrate level” for losing or maintaining weight [3]. The dieter is permitted to eat unlimited amounts of noncarbohydrate foods “when hungry,” but, as noted above, the diet tends to suppress appetite. The plan calls for checking one’s urine for ketone bodies to ensure that the desired level of ketosis is reached. Atkins also recommended large amounts of nutritional supplements. Some physicians prolong the “induction” phase under monitoring.

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Stephen Barrett, M.D.

The Atkins Diets - Rules of Induction

  You may eat pure protein (meat, fish and shellfish, poultry, eggs) and pure fats (butter, olive oil, mayonnaise).
  Eat no more than 20 grams of carbohydrates a day in the form of salad and other vegetables, such as asparagus, broccoli and kale.
  Eat absolutely no fruit, bread, grains, starchy vegetables or dairy products other than cheese, cream or butter.
  Eat out as often as you wish. Just be alert to hidden carbs in gravies, sauces and dressings.
  Eat no food not specifically allowed.
  Aspartame may stimulate insulin production; avoid it and foods containing it.
  Check the carb content of all foods you are unsure about with a carbohydrate gram counter.
  Caffeine stimulates the production of insulin, so avoid regular coffee, tea and cola drinks.
  Eat the amount of food that makes you feel satisfied, but not stuffed. If you’re not hungry, eat nothing or have a small protein snack to accompany your supplements.