"Low-carb diets have been linked to increased frequency of colon cancer, formation of kidney stones, kidney disease, and even osteoporosis," says Neal Barnard, MD, president of the Physicians Commission for Responsible Medicine, a nonprofit research group based in Washington. "The weight loss you see in low-carb diets isn't all that much better than what you see in studies of low-fat, vegetarian diets."
Putting it more bluntly is Kiku Collins-Trentylon, a sports trainer in New York City, who says it's "a pretty evil diet. We all want to sit on our couches, eat nonstop, and have perfect, sculpted bodies. Unfortunately, it doesn't work that way."
Meat is the culprit in low-carb diet danger, says Barnard.
"The reason for the health worries is in large part due to red meat," he says. "People who eat meat every day have three times greater risk of developing colon cancer. And then there is the problem of the kidneys. They aren't designed to work on an oil slick of fat."
Big, Fat Controversy
In the summer of 2002, however, both Time magazine and The Sunday New York Times Magazine have published much-talked-about stories that say Atkins may not be as bad for heart health as previously believed. These stories were sparked in part by a recent study from researchers at Duke University showing most people who ate a high-protein, low-carb diet for six months lost 20 pounds.
That much was expected. What wasn't expected was that the researchers didn't see strong evidence of the diet causing any health problems. In fact, both LDL "bad" cholesterol and HDL "good" cholesterol improved.
The Duke study shows part of why the diet is so popular -- it can produce significant weight loss. What's more, it produces it without a lot of annoying calorie counting and the irritability associated with diets.
Known for Easy Weight Loss
"You're not as hungry as with other diets, and that is a really good thing," says Jenny Anderson, an Internet consultant from Mamaroneck, N.Y., who is on the diet. "That makes it easier to stay on it. So does seeing results fairly quickly. One bad thing is that it forbids caffeine, and I had a lot of bad headaches from coffee withdrawal."
Another drawback to the low-carb diet is its severely limited menu options.
"At first, eggs and bacon in butter for breakfast every day is fun, but day after day of only meat and fat at every meal can get tiresome," says Anderson.
So therein lies the controversy. On one hand you have lots of stories of significant weight loss on a relatively user-friendly diet. On the other, you have dietitians and nutritionists who maintain that the weight loss produced is short-term and can threaten a person's overall health, despite the fact that the weight loss itself may have the beneficial effect of lowering cholesterol.
Who is right? Maybe both sides. It provides weight loss at a very high cost to overall health, or at least that has been the prevailing medical opinion.
"There have been reports in the medical literature that say that this low-carb diet may not be as bad as we thought," says Susan Barr, registered dietitian in New York City. "That makes people interested again in this diet, but until there is more research on what stresses the diet places on the body, there is no way to know what it might be doing besides providing short-term weight loss."
But Is It Safe?
According to the American Dietetic Association, low-carbohydrate diets trigger short-term weight loss through a process called ketosis. This process kicks in when your body is in short supply of carbohydrates, a prime source of energy for the entire body, but especially for the brain, which operates exclusively on carbohydrates.
During ketosis, your carbohydrate-depleted body grabs other sources, including ketones from stored fat or protein from muscle, to satisfy daily energy needs. This can lead to ketoacidosis, a state similar to that of diabetes. This type of diet can trigger weight loss, but it can have the kinds of negative long-term effects on health that Barnard mentions.
The other big question is whether low-carb weight loss lasts.
James Hill, PhD, is director of the Center for Human Nutrition at the University of Colorado Health Sciences Center in Denver. He runs the National Weight Control Registry that includes information on the diets of more than 2,600 people who maintained at least a 30-pound weight loss for a year or more.
What the registry shows, according to Hill, is that less than 1% had followed a diet similar to the Atkins program. Most followed high-carbohydrate, low-fat diets.
But a new, long-term study may resolve the risk-benefit question for low-carb diets.
The Atkins diet has never been evaluated in a large, randomized controlled trial -- the only type of study that convinces doctors that something works, or doesn't -- until now. The National Center for Complementary and Alternative Medicine is funding such a study. Gary Foster, PhD, a psychologist with the University of Pennsylvania's Eating Disorders Clinic is heading this new study to assess the short-term and long-term effects of the Atkins diet in 360 obese men and women.
According to Foster, study participants will be randomly assigned to the Atkins diet (low-carbohydrate, unlimited fat and protein) or a conventional high-carb, low-fat diet. When the study is complete, Foster and his colleagues will have gone a long way toward answering the nagging questions about Atkins and other low-carbohydrate diets.