| CBSHealthWatch- Library - High Fat, Low Carbs, What's the Harm High Fat, Low Carbs, What's the Harm?
Jean Lawrence, Medical Writer What's old has become new again as another generation seeks a quick, easy, and pleasant way to shed excess pounds. High protein, low carbohydrate diets are now all the rage. Your family members and co-workers--even you--may already be on the regimen, which is highly touted by Dr. Robert C. Atkins in his book, Dr. Atkins' New Diet Revolution, and by newcomers to this 30-year-old approach such as Drs. Michael R. Eades and Mary Dan Eades in Protein Power. Almost nightly, we see reports of grinning dieters chowing down on plates of bacon and eggs and bunless bacon cheeseburgers. However, even if "used as directed," these diets are potentially dangerous. "Nobody wants to hear this," groans Dr. James W. Anderson, professor of medicine and clinical nutrition at the University of Kentucky School of Medicine in Lexington. "People lose weight, at least in the short term. I am not arguing with that. But this is absolutely the worst diet you could imagine for long-term obesity, heart disease, and some forms of cancer. If you wanted to find one diet to ruin your health, you couldn't find one worse than Atkins'." Just Water Weight?"The reason you do lose weight so rapidly on this," explains Anderson, "is that you are not eating carbohydrates, which are usually converted to quick energy, so you are burning glycogen, a quick energy supply stored in your liver alongside a supply of water. When you burn the glycogen, the water is excreted. Most of the weight you lose at first is that water." After the 2-week "induction period" of small amounts of carbs prescribed by Atkins, dieters are allowed to phase some carbohydrates back into their reinvented lifetime diet. "As soon as sugar or starch crosses your lips," Anderson says, "you may find that water coming back on board." "People are not stupid," according to Anderson. "While they are on this diet, people will bypass the doughnuts and eat less food, even though the food they eat is fattier. This results in a decreased caloric intake. Voila! Weight loss over time." Will these dieters keep it off? "That is the question," says Dr. Robert H. Eckel, professor of medicine and head of the Nutrition Center at the University of Colorado--and chairman of the Nutrition Committee of the American Heart Association. Even the studies Atkins cites, he says, are old. There are not good studies. "People are ketotic, they are burning glycogen, so they are not hungry. They lose weight. "But," Eckel continues, "I would be worried about someone eating a lot of bacon and eggs to lose weight. What about heart disease? Cancer? Diabetes?" Lose One Risk Factor, Gain Another?A diet high in fat has been suggested to contribute to a number of serious conditions. So far as heart disease goes, doesn't Atkins contend that his diet actually lowers cholesterol? "Cholesterol is only one risk factor of heart disease," points out Ivonne Cottrell, a registered dietition with the Mayo Clinic in Scottsdale, Arizona. "Actually, I have had people come to me on this diet who had lowered their cholesterol and others who have seen theirs go up significantly." "Cholesterol goes down when you lose weight," Anderson says. "It's the loss of the weight. If you try to maintain the weight loss by alternating high fat and 'normal' days, cholesterol could climb." Some forms of cancer--breast, prostate--have been linked to high fat consumption, Eckel notes. Diabetes, too, is linked to fat. "My heavens," exclaims Anderson, "we did part of the research here that convinced the American Diabetes Association to recommend a low-fat diet for treatment and prevention of diabetes. Diabetes is best treated with high carbohydrate, high fiber, low glycemic [sugar], and low energy density foods." High protein diets also strain the kidneys in susceptible people. "People eat more protein than they need now," observes Cottrell. "We have 18 million diabetics in this country, 50 million people with high blood pressure. They can have kidney problems--and high protein intake will bring them on faster," Anderson adds. Obviously excess weight puts a strain on your heart. Would removing some of that strain balance out the artery-hardening potential of the high-fat diet? None of these authorities would say that. "This diet is thrombogenic," Anderson thunders. "This means the fat will tend to form lipid particles in your blood after meals, which could lead to blood clots, meaning heart attack or stroke. "We worry about this," he continues, "because many of the people who love these diets are men aged 40 to 50, who like their meat. They may be 5 years from their first heart attack. This couldn't be worse for them. Did you know that for 50% of men who die from heart attacks, the fatal attack is their first symptom? They will never know what this diet is doing to them." "People just don't want to eat healthy," Anderson concludes. Might the saving grace be that the diets are so rigid and boring that people cannot stick with them? "Some people are fanatics. I saw a man in Time magazine who had been on it a year," he counters. "They may lose some weight, but all I can say is they are doing their blood vessels no favor." "The diet went away before because people found it didn't work," Cottrell says. Could that have been a lilt of hope in her voice?
Dec.1999
© 1999 by Medscape Inc. All rights reserved.
Jean Lawrence is a medical journalist based in Chandler, Arizona.
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