The Diet Debates Are Over
Find what really should be included in a heart-healthy diet.
By Arthur Agatston, MD, Everyday Health heart expert
Today, the diet debates are over. We have moved beyond the confusion of the low-fat versus low-carb battles to an expert consensus on what constitutes a healthy diet. Health-care professionals now agree that our focus should be on nutrient-dense, fiber-rich carbohydrates, healthy sources of unsaturated fats, low-fat dairy, and lean sources of protein, and this is reflected in the new USDA food pyramid. Undoubtedly, ongoing research will continue to add a great deal to our knowledge of the benefits of individual foods, but the basic principles of healthy eating are not going to change.
To better understand how we as a nation got into the health mess we are in and how we have come to the present consensus of opinion, it's important to be aware of some relevant history.
When I began work on the South Beach Diet, the only other diets recommended for heart patients were either the standard low-fat, low-calorie eating plan endorsed by the American Heart Association or the even stricter, extremely low-fat regimens popularized by Dean Ornish, MD, and Nathan Pritikin. At the time, telling patients to eat fat of any sort was medical heresy.
The premise of the low-fat diet was simple. Experts believed that the American diet was too high in fat. They based their belief, in part, on a major study published in the 1970s that compared a society's diet to its rate of heart disease. The study, which was conducted by a brilliant researcher named Ancel Keys, PhD, of the University of Minnesota, identified a direct correlation between fat intake and heart attack. Dr. Keys's study found that residents of the United States and certain countries in Europe had both the highest intake of total fat and the highest rate of heart attack. Countries with lower fat intake had much lower rates of heart disease. It was well known that people in less developed countries with very low fat intakes had almost no heart attacks.
The study identified one exception to the rule. In Crete, people ate a relatively high-fat diet but still had low rates of heart disease. Since the results for Crete were not consistent with the rest of the study, they were discounted. What the researchers did not appreciate at that time was that, although the typical Crete diet was high in fat, the fat was "good" fat from olive oil, fatty fish, and nuts, not the bad saturated fat that was consumed in the countries whose populations had the highest rates of heart attack. What they also didn't understand was the fact that people who lived in countries that consumed the least amount of fat also ate the highest amount of fiber, which we now know is protective against heart disease. In fact, in 1980, when Dr. Keys wrote a book summarizing his research, he suggested that fiber may have been an important variable not taken into account at the time of his study. This was not an oversight, because the role of fiber in nutrition was not known at the time of his study.
But the initial response of the medical community to Dr. Keys's earlier study was to fixate on fat, specifically on how bad it was. The message became "Get the fat out." As a result, people were given advice such as "Avoid oils" and "Eat your salads dry if you can" and "Use only fat-free salad dressings." Moreover, because protein was a major source of fat in the diet, low fat often meant eating less red meat, chicken, fish, and dairy and making up for it with lots of sugary and starchy refined carbohydrates.
The problem with the low-fat, high-carb recommendations was that they did not distinguish between good, high-fiber carbohydrates (such as whole fruits, vegetables, and whole grains) and refined, low fiber, high-sugar carbs (such as white bread and muffins). If the packaging said a food was "low fat," it didn't matter if it had a high sugar or high starch content and virtually no nutrient value; it was considered to be okay.
The war on fat not only kept people away from bad saturated fat but led to the development of trans fats (which, in the form of partially hydrogenated oils, were invented to replace saturated fats like palm and coconut oils but turned out to be much worse). It also prevented them from getting the good, heart-healthy polyunsaturated omega-3 fatty acids found in cold-water fish and flaxseeds, for example, and the good, heart-healthy monounsaturated fats found in foods such as olive oil and nuts.
Through the 1980s and early 1990s, I watched my patients, the country, and frankly myself struggle with the so-called heart-healthy low-fat, high-carb diet. We tried our best to stick with it, but we were always hungry and rarely satisfied. What was even more distressing to me was that I saw problems in my patients' blood chemistries as we began to measure triglycerides and good HDL in addition to total cholesterol and LDL. I observed that some patients' triglycerides rose in response to the strict low-fat, high-carb diet they were following. We now know that a high triglyceride level is often the body's response to excess sugar and starch in a person's diet. But back then, this wasn't well understood. To help my patients, I even tried the then new, magic-bullet statin drugs Mevacor and Pravachol, but the patients' triglyceride levels hardly budged. Furthermore, with the low-fat diet, their LDL cholesterol was also affected: It would go down a few points, which was good, but then it would return to baseline or go even higher. My experience with these patients was corroborated in the clinical trials I was reviewing at the time.
Last Updated: 11/18/2008
Reprinted from: THE SOUTH BEACH HEART PROGRAM by Arthur Agatston, MD. Â© 2007 by Arthur Agatston, MD. Permission granted by Rodale, Inc., Emmaus, PA 18098. Available wherever books are sold or directly from the publisher by calling (800)
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