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The Atkins Diet

Introduction

The Atkins Diet is a high-protein, high-fat, and low-carbohydrate weight loss diet originally developed by Robert C. Atkins, M.D. It is based on the belief that diets high in sugar and other refined carbohydrates increase the production of insulin, a hormone that stimulates the storage of calories as fat. The Atkins diet severely restricts the consumption of carbohydrates, forcing the body to metabolize fat to produce energy, a condition Atkins calls Benign Dietary Ketosis (BDK). Although the diet can induce rapid weight loss, it also restricts important food groups, such as grains, fruits and dairy products. For this reason, the Atkins diet does not provide all the nutrients needed by pregnant or lactating women, athletes and children. It may also be inappropriate for people with kidney disease.

History

Atkins first developed this diet in the 1960s. Considered highly controversial, its popularity waxed and waned. In the early 1990s, Dr. Atkins brought his diet back into the nutrition spotlight with the publication of his best-selling book Dr. Atkins' New Diet Revolution. According to this book, Dr. Atkins and his colleagues at The Atkins Center for Complementary Medicine in New York have used this diet to successfully treat obesity, as well as Type 2 diabetes, high cholesterol, elevated triglycerides, and high blood pressure.

Popularity

Dr. Atkins New Diet Revolution has been on the New York Times paperback bestsellers list for more than four years. It is estimated that more than 20 million people worldwide have tried the Atkins Diet.

Principles

The basic premise of the Atkins Diet is that calories don't matter — a revolutionary and refreshing concept for anyone who has tried unsuccessfully to lose weight by tediously counting the calories in every bite of food. While severely restricting the consumption of carbohydrate-rich foods, the Atkins Diet encourages unlimited consumption of foods containing protein and fat.

Dr. Atkins' recommendations are based on his belief that diets high in sugar and refined carbohydrates increase the production of insulin, a hormone secreted by the pancreas. Insulin facilitates the storage of calories as fat. When less carbohydrates are consumed, less insulin is secreted, resulting in less fat storage. In addition, the lack of available dietary carbohydrate (the body's preferred source of fuel) forces the body to burn stored fat as energy, a condition Dr. Atkins refers to as Benign Dietary Ketosis (BDK).

Even a small amount of carbohydrate in the diet will prevent Benign Dietary Ketosis, preventing weight loss in individuals on the Atkins Diet. As a result, Atkins dieters are encouraged to test their urine for the presence of ketones (fat-like compounds produced during ketosis) using Lipolysis Testing Strips. If the dieter is in a state of ketosis, he/she will excrete ketones in his/her urine, and the Lipolysis Testing Strip will turn purple. If the Lipolysis Testing Strip does not turn purple, the dieter must restrict his/her carbohydrate intake further to induce BDK.

The Atkins Diet is divided into four phases: Induction, Ongoing Weight Loss, Premaintenance, and Maintenance.

During the Induction phase (the first 14 days of the diet), carbohydrate intake is limited to no more than 20 grams per day. No fruit, bread, grains, starchy vegetables, or dairy products (except cheese, cream and butter) are allowed during this phase.

During the Ongoing Weight Loss phase, dieters experiment with various levels of carbohydrate consumption until they determine the most liberal level of carbohydrate intake that allows them to continue to lose weight. Dieters are encouraged to maintain this level of carbohydrate intake until their weight loss goals are met.

During the Premaintenance and Maintenance phases, dieters determine the level of carbohydrate consumption that allows them to maintain their weight. To prevent regaining weight, dieters must stick to this level of carbohydrate consumption, perhaps for the rest of their lives.

According to Dr. Atkins, most people must limit their carbohydrate intake to no more than 60 grams per day to keep lost weight off. (Note: The dietary recommendations issued by various organizations, including the United States Department of Agriculture, the National Institutes of Health, and the American Heart Association, encourage a daily carbohydrate intake of approximately 300 grams.)

In addition to the dietary restrictions discussed above, Dr. Atkins recommends regular exercise and nutritional supplementation as part of his weight loss program.

Research

Dr. Atkins' assertion that calorie restriction is not necessary for weight loss stands in direct conflict with the vast majority of research studies. The scientific support for Dr. Atkins' assertion is rooted primarily in a paper published in the Lancet in 1956 by Kekwick and Pawan. This paper reported the results of a series of small clinical trials in which obese participants were given reduced, normal, and increased calorie diets with varying macronutrient (protein, carbohydrate and fat) compositions for seven to nine days. In these experiments, participants experienced more dramatic weight loss when eating a normal or reduced calorie diet composed primarily of protein or fat than when consuming a diet containing mostly carbohydrates.

Of special significance was the observation that weight loss occurred when a high fat diet containing 2,600 calories was consumed, while participants eating a high carbohydrate diet containing fewer calories (2,000 calories) maintained or gained weight. The authors of this report concluded that the amount of weight loss measured with the high protein and high fat diets was greater than that explained merely by fluid loss, and that some aspect of metabolism had been enhanced. According to Dr. Atkins, these results support his recommendation to restrict carbohydrate intake and to eat unlimited quantities of protein and fat.

In the several years following the publication of this paper, several other researchers attempted to replicate the results obtained by Kekwick and Pawan. (Olesen 1960, Yudkin 1960, Pilkington 1960) In these papers, the researchers reported weight loss with a low-carbohydrate, high-fat diet, but concluded that weight loss was the result of a reduction in caloric intake and fluid loss, and no support was found for the Kekwick and Pawan's theory that a high-protein and/or high-fat diet enhanced metabolism. Furthermore, the Kekwick and Pawan study, by the authors' own account, was flawed. Kekwick and Pawan wrote: "In such a study, the difficulties are formidable. The first and main hazard was that many of these patients had inadequate personalities. At worst they would cheat and lie, obtaining food from visitors, from trolleys touring the wards, and from neighboring patients. At best, they cooperated fully, but a few found the diet so trying that they could not eat the whole of their meals. When this happened, the rejected part was weighed, and the equivalent calories and foodstuffs were added to a meal later in the day. The results we report are selected, a considerable number of known failures in discipline being discarded." As a result of these difficulties noted by Kekwick and Pawan, it is impossible to determine exactly how many calories were consumed, and any conclusions drawn from the data should be viewed with skepticism.

A large body of scientific research conducted since the 1950s supports the view held by most nutrition experts that moderate caloric restriction, independent of the protein, fat and carbohydrate content of the diet, is the key variable associated with weight loss. (Golay 1996, Golay 1996, Pena 1979, Lean 1997, Kennedy 2001) However, even critics of the Atkins Diet concede that significant, short-term weight loss is possible with the diet. The reason is that the high amount of protein and fat in the diet promote satiety (Hill, 1986, Latner 1999), which allows dieters to eat fewer calories without feeling intense hunger or cravings. In addition, the Atkins Diet causes fluid loss that results in a reduction in weight. Due to the restriction of carbohydrates, the Atkins Diet depletes glycogen stores (glycogen is the form in which the body stores carbohydrate in muscle). Since each gram of glycogen is hydrated with 2-3 grams of water, when glycogen stores are used, this water is liberated and sent to the kidneys for excretion, so dieters experience rapid water loss.

Nutrition experts caution that no long-term studies have been conducted to assess the impact of the Atkins Diet and worry that the diet may have adverse health effects when followed for an extended period of time. From a conventional nutrition standpoint, the Atkins Diet is of poor nutritional quality in that it is deficient in several nutrients important for health and contains excessive amounts of nutrients that people should limit (see Nutrient Excess/Deficiencies below). Specifically, the diet is low in dietary fiber and high in saturated fat, two dietary conditions associated with an increased risk for cancer and cardiovascular disease. In fact, Anderson et al. estimated that due to the excessive intake of saturated fat, long-term use of the Atkins Diet would increase serum cholesterol levels by approximately 25%. (Anderson, et al.)

In a paper published in 2001, the United States Department of Agriculture (USDA) reported the results of a study initiated to examine the relationship between various prototype popular diets (including low-carbohydrate diets such as the Atkins Diet) and diet quality (Kennedy 2001). In this study, diet quality was measured by the Healthy Eating Index (an index based on the diet recommendations of the Food Guide Pyramid and the U.S. Dietary Guidelines) and body mass index (a ratio of height to weight). The researchers found that the Healthy Eating Index was significantly higher for high-carbohydrate diets than for low-carbohydrate diets. In addition, the body mass indices of men and women on high carbohydrate diets was significantly lower than those of individuals eating a low-carbohydrate diet.

Foods Emphasized

The Atkins Diet emphasizes the consumption of protein and fat. Individuals following the Atkins Diet are permitted to eat unlimited amounts of all meats, poultry, fish, eggs, and most cheeses. In addition, all vegetable oils are allowed, as are high-fat condiments such as butter, sour cream, mayonnaise, and guacamole. Small amounts of non-starchy vegetables and certain fruits (for example, cantaloupe and berries) are allowed.

Foods Avoided

The Atkins Diet restricts the consumption of carbohydrates. As a result, bread, pasta, cereals, starchy vegetables, dairy products (except cheese, sour cream, butter, and heavy cream), many fruits, and foods containing refined sugars must be avoided.

Nutrient Excesses/Deficiencies

Depending on the foods chosen by the dieter, the Atkins Diet may contain a large amount of saturated fat and cholesterol. Anderson, et al. analyzed a seven-day sample menu plan from the Atkins Diet. In this analysis, the Atkins Diet provided a daily intake of 1,600 calories, 104 grams of total fat, 47 grams of saturated fat and 924 mg of cholesterol. In comparison, the dietary guidelines issued by the United States Department of Agriculture for a 2,000 calorie diet recommend limiting daily intake of total fat, saturated fat, and cholesterol to 65 grams, 20 grams and 300 mg, respectively.

The lack of grains, fruits and vegetables in the Atkins Diet may lead to deficiencies of key nutrients including vitamin C, folic acid, and several minerals. Furthermore, in the analysis conducted by Anderson et al., the Atkins Diet provided a meager 4 grams of dietary fiber per day.

Who Benefits

The Atkins Diet can lower insulin levels and promote quick weight loss. As a result, this diet may be useful as a short-term weight loss diet for overweight and obese individuals with insulin resistance and hyperinsulinemia. (Gumbiner 1996, Baba 1999, Piatti 1994)

Who is Harmed

The Atkins Diet is a relatively low-calorie diet that restricts major food groups including grains, fruits, and dairy products. Such diets are not typically recommended for pregnant or lactating women, children, or others with increased caloric and/or nutrient needs.

Due to the lack of carbohydrate (the body's preferred source of fuel for muscles) in the Atkins Diet, the diet is also not recommended for athletes or individuals who engage in regular, high-intensity exercise.

In addition, anyone with existing cardiovascular disease, or those at high risk for cardiovascular disease, should be aware that following this diet for a long period of time may increase blood cholesterol levels.

The high protein content of the Atkins Diet stresses the liver and kidneys (Stein 2000). As a result, anyone with liver or kidney disease should avoid this diet.

Menu Ideas

The following menu ideas are taken from Dr. Atkins New Diet Revolution and are representative of the type and quantity of food eaten during the various phases of the diet.

Induction Menu

Breakfast

  • Eggs, scrambled or fried, with bacon, ham, or Canadian bacon
  • Decaffeinated coffee or tea

Lunch

  • Bacon cheeseburger, no bun
  • Small tossed salad
  • Seltzer water

Dinner

  • Shrimp cocktail with mustard and mayonnaise
  • Clear consommé
  • Steak, roast, chops, fish or fowl
  • Tossed salad
  • Diet Jello with a spoonful of whipped cream (unsweetened or artificially sweetened)

Ongoing Weight Loss Menu

Breakfast

  • Cheese omelet
  • 3 ounces of tomato juice
  • Bran Crispbread (amount containing 2 grams of carbohydrate)
  • Decaffeinated coffee or tea

Lunch

  • Chef's salad with ham, cheese, chicken, egg and oil and vinegar dressing
  • Iced herbal tea

Dinner

  • Seafood salad
  • Poached salmon
  • 2/3 cup of vegetables
  • 1/2 cup of strawberries (in heavy, unsweetened cream)

Maintenance Menu

Breakfast

  • Cheese and spinach omelet
  • 1/2 cantaloupe
  • Bran Crispbread (amount containing 4 grams of carbohydrate) with butter
  • Decaffeinated coffee or tea

Lunch

  • Roast chicken
  • 2/3 cups of vegetables
  • Green salad with creamy garlic dressing
  • Club soda

Dinner

  • French onion soup
  • Salad with tomatoes, onions and carrots with any no-carbohydrate dressing
  • 1 cup vegetables
  • 1/2 small baked potato with sour cream and chives
  • Lightly breaded veal chops
  • 1 cup fresh fruit compote
  • Glass of dry wine

Resources

The official web site of the Atkins Diet is located at www.atkinsdiet.com. In addition, Dr. Atkins has written several books:

References