Orlando, FL - A debate tackling the relative merits of two of the most commonly touted heart-healthy diets reached no palpable conclusions and offered little new food for thought. As debate moderator Dr Prediman K Shah (Cedars-Sinai Medical Center, Los Angeles, CA) observed to a bemused audience at the American College of Cardiology 50th Scientific Session, the major tenets of two diet theories are "diametrically opposed," causing confusion for patients, not to mention their doctors.

Dr Robert C Atkins (Atkins Center for Complementary Medicine, New York, NY) argued in favor of his low-carbohydrate, high-protein, high-fat diet, while Dr Dean Ornish (Preventive Medicine Research Institute, Sausalito, CA) pushed his low-fat, vegetarian diet and "life choice" diet. Both men have published books extolling their own methods.

According to Atkins, "The government has been pushing a low-fat, high-carbohydrate diet that is creating an epidemic of insulin resistance and hyperinsulinemia."

Atkins' oft-reiterated stance was "not as a scientist but as a clinical practitioner" with a track record of 41 years and 20 000 patients. His argument rested on "massive evidence" suggesting that elevated triglycerides in tandem with cholesterol levels are a "pre-eminent" risk factor for CVD. He cited studies supporting his theory that low-carbohydrate diets (and not just low-calorie diets) lower triglycerides and create a "metabolic shift" such that an "alternate metabolic pathway" is used by the body to burn fat. High-carbohydrate diets, Atkins argued, increase triglyceride levels, leading ultimately to insulin disorders, diabetes, obesity, and heart disease.

Eschewing the fat

In his counter argument, Ornish began by acknowledging that the whole area of heart-smart diets "is very confusing for many people" and that "a little knowledge is a dangerous thing and that is certainly an issue here."

The lack of scientific proof supporting Atkins diet surfaced as a faithful chorus line in Ornish's argument, as did his insistence that there are no long-term data supporting Atkins's claims.

A low-fat, high-complex carbohydrate diet by contrast, stated Ornish, has been more "scientifically" established as helping people prevent heart disease, maintain a healthy lifestyle, and even reverse disease. It is this last factor that helped Ornish to garner some credibility for his methods, following publication of his Lifestyle Heart Trial in the December 16, 1998 issue of JAMA.

All this talk about food made some delegates hungry

Throughout the ACC debate, Ornish repeatedly asserted that his method targets the underlying disease process, whereas Atkins' diet was geared towards lowering a single risk factor for disease and not the disease itself. When much of the existing scientific evidence points to the harms and not the benefits of a high-fat, high-protein diet, says Ornish, Atkins' diet only serves to "mortgage" long-term health for the sake of short-term pleasures. "I may be old fashioned," Ornish carped, "but I believe you should first have the scientific data, then write the book."

	I may be old fashioned, but I believe you should first have the scientific data, then write the book.

BR> Atkins' rebuttal dwelt heavily on his own clinical experience saying he'd seen his patients improve hundreds and thousands of times. "Dr Ornish is hooked on the idea that the proof hasn't come as yet, and I agree at the same time it is quite obvious from my own observations and all the other studies related to this that the proof will come and it will work out the way it does in the practice of medicine."

Ornish and Atkins jointly acknowledged the need for rigorous scientific analysis of the high-protein, high-fat diet, potentially compared to a high-carbohydrate, low-fat diet, with the specific outcome of preventing or reducing coronary artery disease. They also agreed - reluctantly - on the need to purge America's passion for simple carbohydrates, likely culprits in the obesity epidemic across North America and elsewhere.

The brief compromise, however, was short lasting. "The goal," griped Ornish, "is not to go from simple carbohydrates to bacon, but rather from simple carbohydrates to complex carbohydrates."

Sources

1.Ornish D, Scherwitz LW, Billings JH, et al. Intensive lifestyle changes for reversal of coronary heart disease. JAMA 1998 Dec 16; 280(23):2001-7.

Shelley Wood shelley@conceptis.com

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