To Your Health

A. A storm of controversy still surrounds Dr. Atkins and his very-low-carbohydrate weight-loss diet, despite 30 years of research aimed at resolving the debate. His recent accidental death has not calmed the debate.

At the heart of the controversy is the metabolic condition called ketosis. Ketosis develops when dietary carbohydrate intake is not sufficient to meet the energy requirements of the body, and the body switches to primarily using fat for energy. Fatty acids are released into the bloodstream where they are converted to ketones. These ketones are then used for energy by muscles, the brain, and other organs, but excess ketones are excreted in urine. Dr. Atkins theorized that ketosis is as much a factor in weight loss as calorie reduction because the energy of the ketones is excreted and lost, rather than being stored in fat cells for future re-use by the body.

Within the past year there has been some research that may vindicate Atkins' position, but unfortunately it was funded by the Atkins Foundation and thus may not be entirely objective. This study demonstrated that ketosis brought on by limited carbohydrate intake improved the blood markers that are associated with coronary artery disease. After six weeks on an Atkins-style diet, fasting triglyceride level was decreased by 33% and fasting insulin level by 34%. Total cholesterol was unchanged, but HDL cholesterol tended to be slightly increased, suggesting a lowered risk of cardiovascular disease.

However, researchers at the University of Texas Southwestern Medical Center at Dallas have a different view of ketosis. They report that ketosis may pose a serious health problem, including an increased risk of kidney stones and perhaps a higher risk of bone loss. In a study funded in part by grants from the U.S. Public Health Service, researchers reported that urinary acid excretion, which indicates a worsened risk for kidney stones, increased by as much as 90% in subjects on a restricted carbohydrate diet. Chronic increased body acid can also suppress the function of bone-forming cells while stimulating the activity of cells that destroy bone, resulting in decreased bone density.

One factor often left out of the squabble is the ability of people to stick to the diet. The prestigious New England Journal of Medicine, on May 22, 2003, reported on two studies (not funded by the Atkins Foundation) that demonstrate twice as much weight loss during the first six months with a low-carbohydrate diet than with the reduced-fat diet. However, the difference disappears by 12 months into the diet, which may indicate that any approach to weight loss should work if you can maintain it over the long term. For up to 12 weeks about twice as many people are willing to stay on the Atkins diet, compared to a low-fat diet, but very few can maintain it for more than a few months.

The fact is that while some studies have reported benefits from the diet, others have not. No one seems to question the ability of the Atkins diet to produce weight loss, but many wonder if it is a healthy way to lose weight.