Low Carbohydrate Diets
Ellen Coleman, RD, MA, MPH © 2004

The shared theme of many popular weight-loss books (Dr. Atkins' New Diet Revolution, Protein Power, Carbohydrate Addict's Lifespan Program, Sugar Busters, and Enter the Zone) is that carbohydrates cause obesity. These diet books claim that carbohydrates are bad because they raise the blood sugar level and cause the release of insulin – a supposed "monster" hormone that promotes fat storage.

Dr. Atkins' low-carbohydrate, ketogenic diet was first published in 1972 and recycled 20 years later in 1992 as Dr. Atkins' New Diet Revolution (M Evans and Company). Robert Atkins, MD, asserts that obesity exists primarily because of metabolic reasons and that restricting carbohydrate can circumvent this metabolic defect. According to Atkins, individuals can lose more weight by eating a high fat diet than with an equivalent energy intake from a high carbohydrate diet. Atkins recommends no more than 20 grams of carbohydrate per day during the induction phase (two weeks) and recommends daily urine tests to verify the maintenance of the ketosis. He strongly emphasizes high fat foods and avoidance of fruits, vegetables, breads, cereals, and most dairy products.

The authors of Protein Power (Bantam Books, 1996), Michael Eades, MD, and Mary Eades, MD, target insulin as the cause of obesity. The Eades believe that high levels of insulin cause metabolic disturbances in the body leading to hypertension, elevated serum cholesterol and triglyceride levels, diabetes, and obesity. They suggest that restricting carbohydrate overcomes these metabolic disturbances and alleviates medical problems.

The Protein Power diet closely resembles the Atkins diet in nutrient composition. The Eades say that it's fine to eat steak, pork ribs, and other fatty meats as long as people don't load up on starch and sugar at the same time. All that saturated fat is a recipe for clogged arteries. The authors outline methods to determine the amount of protein to consume and give instructions for planning meals that focus on protein. Carbohydrates are limited to 30 grams or less per day. The diet permits limited amounts of fruit and vegetables.

The authors of Carbohydrate Addict's Lifespan Program, Richard and Rachael Heller, claim that an excess of insulin ("hunger hormone") causes the "carbohydrate addict" to experience intense and recurrent cravings and a heightened ability to store fat. The book claims that carbohydrates crank up insulin production, increase appetite, promote fat storage, and cause weight gain.

The Carbohydrate Addict's "Basic Plan" has three essential guidelines: 1) eat a balanced Reward meal every day (one-third craving reducing protein, one-third craving reducing vegetables, one-third carbohydrate rich food; preceded by two cups salad), 2) complete Reward meal within one hour, and 3) eat only craving reducing foods at all other meals and snacks. Following these rules permanently is unlikely for even the most dedicated dieter and takes the pleasure out of eating by treating food as a medical prescription. Furthermore, research does not support the notion of biological "carbohydrate addiction."

The authors of Sugar Busters! (Ballantine Publishing Group; 1998) H. Leighton Steward, Morrison Bethea, MD, Sam Andrews, MD, and Luis Balart, MD, claim that sugar is toxic. The premise of the book is that insulin insensitivity causes obesity and non-insulin dependent diabetes. The Sugar Busters diet focuses on reducing high glycemic carbohydrates (insulin-stimulating carbohydrates) to lower insulin levels and decrease insulin resistance.

The authors recommend that beverages be consumed in small portions during meals. They claim that "washing" food down leads to inadequate chewing and that excess fluid dilutes digestive juices, resulting in partially digested food. There is no scientific evidence to suggest that consuming fluids during a meal negatively affects digestion.

The Zone is defined as the seemingly effortless, euphoric state where body and mind work at peak efficiency. While in the Zone, people can achieve permanent weight loss and optimum health. The author of Enter the Zone (Harper-Collins, 1997) and Mastering the Zone (Harper-Collins, 1997) Barry Sears, PhD, attributes these benefits to altering the production of eicosanoids with the Zone diet.

The major theme of the book is relatively simple – carbohydrates are bad because they raise the blood glucose level and cause the release of insulin, resulting in obesity. Sears further claims that a carbohydrate-rich diet increases disease-promoting "bad" eicosanoids, while a Zone-favorable diet increases health-promoting "good" eicosanoids. To enter the Zone, food should be treated as a drug – it must be eaten in a controlled fashion and in the proper proportions. Specifically, this means eating exactly 40% of calories as carbohydrate, 30% as protein, and 30% as fat at each meal and snack.

The Zone diet focuses on lean meats and can include three servings of fowl per day but restricts high fat animal products, high glycemic grain products (grains, breads, pasta and rice), starchy vegetables, and some fruits.

There is no evidence that the 40-30-30 macronutrient composition of the Zone diet has an effect on body weight independently of the energy content of the diet. There is also no proof that carbohydrate makes "bad" eicosanoids or that the Zone diet makes "good" eicosanoids.

Next: "Effective Weight Reduction"