Atkins' Diet Update

The New York Times ran an article titled “What if it has all been a big fat lie?” in its July 7,2002 magazine. Gary Taubes, the author, says he talked with leading nutrition experts and claimed that eating a potato worsens blood lipids and eating a porterhouse steak or even lard out of the can will improve blood lipids and probably reduce the risk of heart disease. He claims that new research will prove that Atkins’ was right and the U.S. Dietary Guidelines, Food Guide Pyramid and National Cholesterol Education Program are wrong.Atkins’ has funded two recently published studies. One, with no control group, followed 41 subjects who stayed on a ketogenic diet for 6 months.1 This study found no significant change in total cholesterol. However, HDL increased 10 points and LDL fell by 10 points on average. Triglyceride (TG) levels dropped from 130 to 74 mg/dl. All subjects were given supplements including supplements of omega 3 fatty acids that can lower TGs and increase HDL. Both TGs and TC would be expected to drop in response to weight loss and HDL would be expected to increase. On average the subjects lost about 20 pounds over 6 months. Most subjects reported constipation and bad breath, half reported headaches and 10% complained of hair loss.The other study had just 20 subjects who either followed their typical diet or were assigned to the Atkins’ diet for 6 weeks. TC, LDL and HDL levels all increased, but not significantly, and serum TG dropped significantly by 33%.2 Those on the ketogenic diet lost 5 lbs while the control group gained about 1 lb after 6 weeks. Not surprisingly, after 6 weeks on the high-fat, ketogenic diet, postprandial lipemia, in response to a high-fat meal, was reduced by 29%. Had these researchers instead challenged these subjects with a high-carbohydrate meal they would have found much higher postprandial glycemia. It is not new or surprising that people metabolically adapt to the mix of macronutrients in their diet.What impact these modest changes in blood lipids might have on atherosclerosis and other disease processes requires far more research. Another study showed that a ketogenic diet increased calcium excretion and so could lead to kidney stones and osteoporosis. More research is needed for an Atkins’-type diet before it’s advocated as a safe and effective treatment for long-term weight control. Watch for an updated CPE?course on this diet.1. Am J Med 2002;113:30-62. J Nutr 2002;132:1879-85