Sunday, March 24, 2019

Retrospective #36: The South Beach and Mediterranean Diets

This column inaugurates a two-part series on prophylactic and therapeutic diets. We make this distinction because we think it is unrecognized in the public health community and specifically the “Dietary Guidelines for Americans.” As a consequence, most medical practitioners are unaware of it and, in my experience, diabetes educators simply refuse to accept it. The result:  the public does not see the importance of the distinction to health and wellbeing.
I just roll by eyes in disbelief every year when I read that U.S. News and World Report had a panel of experts rate 25 diet plans and that Weight Watchers and Jenny Craig were among the top rated. These programs are based on a “balanced” diet, eating less, and exercising more. The reason they continue to be popular, I think, is that the subscriber keeps coming back year after year, after regaining the weight they lost before. They are prophylactic in the sense that, if they have not yet manifested, the goal is to prevent the myriad consequences to health of being overweight. For a discussion of the consequences, scroll down to Retrospective #9, “Metabolic Syndrome.”
The South Beach Diet
The South Beach Diet, a trademarked term, is a popular non-subscription trend in dieting. Created by cardiologist Arthur Agatston and dietician Marie Almon, this prophylactic diet rejects the low-fat approaches of the Ornish Diet and the Pritikin Diet, advocated by the American Heart Association since the 1950’s. However, Agatston accepts the now largely discredited dogma that low-fat diets “reduce cholesterol and prevent heart disease.” So, it should be no surprise that the South Beach Diet discourages all saturated fats and favors unsaturated fats. Big mistake!
The South Beach Diet is relatively simple in principle: Replace “bad carbs” and “bad fat” with “good carbs” and “good fat.” The glycemic index is the scale on which “bad carbs” and “good carbs” are measured.
Sugar is a simple, 2-molecule carbohydrate compound which breaks down easily to free up glucose for energy. Long-chain carb compounds are also broken down to glucose by the digestion process. Whole food carbs, aka “complex carbohydrates,” break down more slowly; processed carbs, as in flour in bread for example, break down very quickly, leading to cycles of hunger. As a result, patients were consuming excess calories and gaining weight. Ironically, the attempt to reduce the risk of heart disease actually increased it, according to Wikipedia.
In sum, the South Beach Diet favors “complex carbs” and “lean protein.” Eating this way will help to keep your blood sugar steady by avoiding the highly processed, refined carbs that cause drastic swings in blood sugar. Once you stabilize your blood sugar, cravings are virtually eliminated. But before you try this diet, see Retrospective #21.
The Mediterranean Diet
Another popular prophylactic trend in dieting is the Mediterranean Diet. Its origins date to Ancel Keys’s much maligned Seven Countries Study, in which he selected data from 7 countries out of a 22-country study to support his diet-heart or Lipid Hypothesis (see Retrospectives #1 & #3). By 1961 this led to the American Heart Association’s endorsement of the hypothesis and by 1977 to the McGovern Committee’s catastrophic “Dietary Goals.”
Nevertheless, in the 1990’s epidemiologist Walter Willett of Harvard University’s School of Public Health again helped popularize this diet program. Its main tenets are: high amounts of olive oil, the principal source of fat on the diet; low to moderate amounts of dairy products (principally cheese and yogurt), fish, poultry and red wine; and, to avoid cholesterol from animal products, low amounts of eggs and red meat. Again, this is my problem with the diet.
Interestingly, it is a diet high in salt (olives, salt-cured cheese, anchovies, capers, salted-fish roe, and salads dressed in olive oil). It emphasizes abundant plant foods, including legumes, and fresh fruit daily, typically for dessert. The total amount of fat calories in the diet is, however, about 30%, which until 2010 was the upper limit in the Dietary Guidelines for Americans, with less than a third from saturated fats. One of the main differences is the high level of monounsaturated fats, most notable oleic acid, from olive oil. My personal favorite aspect of this diet is the glass or two or red wine daily, although a bowl of berries and cream for dessert once a week sounds pretty good to me too.

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