Friday, May 21, 2010

Health Benefits of a Low-Carbohydrate, High-Saturated-Fat Diet - by Donald W. Miller, Jr., MD

The 60-year reign of the low-fat, high-carbohydrate diet will end. This will happen when the health-destroying effects of excess carbohydrates in the diet become more widely recognized and the health benefits of saturated fats are better appreciated.

“Life imitates art,” Oscar Wilde said, “far more than art imitates life.” In Woody Allen’s film Sleeper, saturated fats are health foods. Miles Monroe, part owner of the Happy Carrot Health Food Restaurant in Greenwich Village, is cryogenically frozen in 1973 after a botched peptic ulcer operation (done at the now closed St. Vincent’s Hospital there). Scientists wake him up 200 years later and have this exchange. Dr. Aragon: “Has he asked for anything special?” Dr. Melik: “Yes. This morning for breakfast he requested something called wheat germ, organic honey, and tiger’s milk.” Dr. Aragon: “Oh yes. Those were the charmed substances that some years ago were felt to contain life-preserving properties.” Dr. Melik: “You mean there was no deep fat? No steak or cream pies or hot fudge?” Dr. Aragon: “Those were thought to be unhealthy, precisely the opposite of what we now know to be true.” Dr. Melik: “Incredible!”

There is good reason to believe that this will prove to be the case in life as well. Saturated fats play many important biologic roles. They are an integral component of cell membranes, which are 50 percent saturated fat. Lung surfactant is composed entirely, when available, of one particular saturated fat, 16-carbon palmitic acid. Properly made with this fat, it prevents asthma and other breathing disorders. For nourishment, heart muscle cells prefer saturated long-chain palmitic and 18-carbon stearic acid over carbohydrates. Saturated fats are required for bone to assimilate calcium effectively. They help the liver clear out fat and provide protection from the adverse effects of alcohol and medications like acetaminophen. Medium-chain saturated fats in butter and coconut oil, 12-carbon lauric acid and 14-carbon myristic acid, play an important role in the immune system. They stabilize proteins that enable white blood cells to more effectively recognize and destroy invading viruses, bacteria, and fungi, and also fight tumors. Saturated fatty acids function as signaling messengers for hormone production, including insulin. And saturated fats signal satiety. Not surprisingly, given all these biological functions, saturated fats make up 54 percent of the fat in mother’s breast milk (monounsaturated fats are 39 percent; and polyunsaturated fats, a tiny 3 percent).

Evidence against fat wilts upon close scrutiny. In his Six Country Study, Ancel Keys ignored data available from 16 other countries that did not fall in line with his graph. The results would have been a clutter of dots all over the place if he had included all 22 countries. In Norway and Holland, people eat a lot of fat but have relatively few deaths from heart disease; and in Chile, where people don’t eat much fat they have a high incidence of fatal heart attacks. In an entertaining 2½ minutes, “Big Fat Lies” on YouTube (available HERE) exposes the fraudulent science supporting this widely cited study. Saturated fat may raise cholesterol somewhat, but primarily HDL cholesterol. The ongoing Framingham Heart Study has come to show that fat and cholesterol are, if anything, healthy. A 30-year follow-up reported that for each 1% mg/dl drop in cholesterol there was an 11 percent increase in all-cause mortality (JAMA 1987;257:2176–80). In another report, one director of the Framingham Study states, “We found that the people who ate the most cholesterol, ate the most saturated fat, ate the most calories, weighed the least and were the most physically active” (Arch Int Med 1992;152:1271–2).

An epidemic of obesity has accompanied the adoption of a low-fat diet. In 1900 only 1 in 150 people were obese, 0.7 percent of the population. By 1950, 9.7 percent of Americans were obese. Now two-thirds of Americans are either overweight (33 percent) or obese (32 percent). The average American weighs 30 pounds more today than he or she did 100 years ago. In 1900 people ate more animal fat and were not exposed to high amounts of carbohydrates in sugar-rich sodas and fruit juices, and to a whole panoply of processed foods sweetened with high-fructose corn syrup.

In the body, dietary carbohydrates, sugars and starch, are converted to glucose, which indirectly directs the pancreas to release insulin into the blood. Insulin not only transports glucose into the cells, it stores glucose as glycogen in the liver and muscles. It is also the primary fat-building enzyme, converting glucose to fat. When the liver and muscles are filled with glycogen, insulin turns excess glucose into body fat. Carbohydrates are the primary cause of weight gain, not fats.

Indoctrinated in low-fat dogma by nutrition authorities, government agencies, and the American Heart Association, I used to advise my heart surgery patients to restrict the amount of saturated fat in their diet and not have more than one egg a week. (My Cousin Sally had eggs and bacon for breakfast most days of her life and lived in good estate to the age of 103, which I then attributed to her having very good genes.) Following the USDA food pyramid, I did not voice any concerns about how many carbohydrates they consumed, from starch in bread, pasta, rice, and potatoes and sugar in fruit, pastry, fruit juices, and soda.

Not now. Now I caution them to watch their carbohydrate intake and advise that they follow a diet like the one Christian Allan, Ph.D. and Wolfgang Lutz, M.D. recommend in the Life Without Bread: How a Low-Carbohydrate Diet Can Save Your Life (2000). Their diet limits carbohydrate intake to 72 grams a day, which is equivalent to 6 slices of bread (somewhat more than the Atkins diet). I urge them to eliminate soft drinks from their diet, including diet sodas, which contain health-damaging aspartame, and drink filtered water instead; to avoid baked goods and condiments that contain high-fructose corn syrup; to stay away from the excitotoxin monosodium glutamate (MSG) used in some restaurants and to enhance the flavor of processed foods; and to scrupulously avoid trans fats, which cause cancer, trigger type-2 diabetes, interfere with immune function, and cause heart disease. But they can eat as many eggs as they please.

For optimum health and weight maintenance, the ideal caloric ratios for the three macronutrients are carbohydrates, 10–15 percent; protein, 15–25 percent; and fat, 60–70 percent of calories. Among the different kinds of fats, saturated fats and monounsaturated fats (olive oil) are good; polyunsaturated fats, except for omega-3 and (a small amount of) omega-6 essential fatty acids, are bad, especially industrially processed vegetable oils; and trans fats are terrible. Saturated animal fat is best obtained from grass-fed beef and pastured chickens, along with nitrate-free, additive-free bacon and sausage; and seafood from wild (not farm-raised) fish.


Related previous post: The Scientist and the Stairmaster: Why most of us believe that exercise makes us thinner—and why we're wrong. - By Gary Taubes

Related link: Fats and Oils

The ‘Security Analysis' of diet and health: Good Calories, Bad Calories: Fats, Carbs, and the Controversial Science of Diet and Health

Good sources of saturated fat are pure butter and coconut oil.

A diet I believe is very healthy: PāNu