The Oz Diet

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Take fat. Of all the parts of the average diet that we've been told to avoid, it's fats that have gotten beaten up the most. The very word seems to be an indictment of the substance: We don't want to be fat, so why in the world should we eat fat?

But fats are by no means universally bad. Monounsaturated and polyunsaturated fats are actually recommended for good health. Monounsaturated fats — canola oil and olive oil — have been found to lower LDL cholesterol (the bad cholesterol) and raise HDL cholesterol (the good kind), thus reducing the risks of atherosclerosis and heart disease. Polyunsaturated fats like omega-3s lower LDL as well as reducing the risk of inflammation, heart disease and many other diseases. And omega-3s are also terrific for brain health. Bad fats generally include saturated fats (found in animal products), trans fats (found in hydrogenated and partially hydrogenated oils) and their cousin cholesterol (found in egg yolks, meats and dairy products). Even this general grouping, however, can be misleading: new research is finding that some saturated fats (like those found in coconut oil) may actually be good for you and that dietary cholesterol may not affect blood cholesterol as much as was once thought. The only fat that is universally accepted as bad is trans fat, and that's now been stripped out of most foods.

The redemption of some fats — in moderation — is also leading to the redemption of the beleaguered egg. As a heart surgeon, I am continually struck by the variability in how people process dietary cholesterol. Most people have little issue with their blood-cholesterol levels after eating foods that are relatively high in cholesterol. But a few struggle with even small amounts of cholesterol in their diet. Those few, however, served as cautionary tales for everyone else, and so eggs and red meat, while dangerous if you eat them in excess, came to be seen as radioactive. Most physicians, however, are now comfortably recommending one egg with the yolk per day as an inexpensive source of high-quality protein, even though a few patients do need to be pulled off the program pending blood-cholesterol tests.

Salt is another example of a demonized compound. While our hearts can't beat without it, too much sodium can increase blood pressure to dangerous levels — but only in 10% of the population, with African Americans being particularly sensitive. The only way to know for sure if you're salt sensitive is to check your blood pressure after you consume salt and compare it with when you've been relatively salt-free. But even if your numbers stay within a healthy range, don't go crazy with the saltshaker. Sodium mingles with other elements in processed foods and stimulates our appetite, so it can help pack on pounds. The good news is that almost all hypertensive people, i.e., those whose resting blood pressure is more than 140/90, will benefit from reducing their salt intake — a simple step that translates to an average of five extra years of life for the typical 55-year-old.

The reputation of red wine has similarly improved, to the delight of oenophiles. Resveratrol, an antioxidant found in grape skins, reduces the impact of bad cholesterol, which in turn reduces the risk of cardiovascular disease. Some animal studies show that it can help reduce obesity and diabetes too. However, since there's relatively little resveratrol in red wine — you'd have to drink 60 liters to get the full benefits — it's best to add this antioxidant to your list of supplements. (See page 62.) Still, you should drink some red wine every day: it has relatively few calories and induces milder hangovers than other sources of alcohol, and it is thought to raise good cholesterol and reduce the bad kind, as well as protect arteries against cholesterol-related damage. Red wine is also usually consumed in the company of others, so it encourages human connection, a very powerful factor in maintaining health.

Chocolate is another source of antioxidants — in this case, in the form of flavonoids, which are what give cocoa beans their pungent taste. The darker the chocolate, the less adulterated with milk and other ingredients it is and the heavier the concentration of flavonoids. Nuts, though high in unsaturated fats and calories, can lower bad cholesterol and help curb hunger. The polyphenols in coffee, which is often shunned by the health-conscious, is in fact the No. 1 source of antioxidants in the Western world and in some studies has been associated with lower incidences of dementia, Parkinson's disease and Type 2 diabetes.