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Saturated fat vs. sugar: a British scientist says sugar's the culprit, not fat, and the mediterranean diet may be the antidote.

In 1970 a landmark medical study (Circulation, Dr. Ancel Keys) concluded that cardiovascular risk could be reduced by cutting overall dietary fat to 30 percent of total energy and, more specifically, cutting saturated fat to 10 percent. Elevated concentrations of LDL cholesterol (low-density lipoprotein, or "bad" cholesterol) derived from saturated fat were thought to increase cardiovascular risk.


The resulting rush to low-fat diets caused the food industry to overuse sugar, to enhance the taste of food from which fat was removed, says Dr. Aseem Malhotra, of Croyden University Hospital, UK, writing in the British Medical Journal October 24, 2013. This, he says, is what was responsible for the last four decades' epidemic of obesity.

There's also increasing evidence that sugar is a possible independent risk factor for metabolic syndrome, a constellation of conditions that includes increased blood pressure, high blood sugar, and excess body fat around the waist (intra-abdominal fat) that increase risk of heart disease, stroke and diabetes, says Dr. Malhotra.

Two-thirds of people admitted to the hospital with a diagnosis of acute myocardial infarction really have metabolic syndrome, says Dr. Malhotra, but 75 percent of these patients have completely normal total cholesterol levels--which would indicate that total cholesterol levels aren't really the issue.

Another recent study, published in the Journal of the American Medical Association, showed that a low-fat diet results in a greater decrease in energy expenditure, an unhealthy lipid pattern, and increased insulin resistance compared to a low-carbohydrate, low-glyce-mic index diet. Further, while decreasing saturated fat consumption reduces the large, "type N' LDL particles, it is the smaller, more dense, type B particles that are implicated in cardiovascular disease, says Dr. Malhotra.

ANOTHER RISK FACTOR EMERGES. The emphasis on decreasing fat consumption has diverted attention from the enormous risk factor of atherogenic dyslipidemia, a factor in obesity, metabolic syndrome, insulin resistance and type 2 diabetes, he says. Atherogenic dyslipidemia is a combination of increased levels of small, dense LDL particles, decreased HDL particles and increased triglycerides in the blood. For people with this condition, a low-carbohydrate diet is beneficial compared to a high-carbohydrate diet, while the total fat or saturated fat in the diet has little impact.

He also contends that the focus on total cholesterol levels has led millions of people to be overmedicated with statins.

THE ANTIDOTE. Dr. Malhotra recommends adopting a Mediterranean diet--low in red meat, high in monounsaturated fats (olive oil), vegetables, fruits, fish, and moderate wine con-sumption--and cites a recently published PREDIMED randomized controlled trial that showed the Mediterranean diet is 30 percent more effective than a low-fat diet in preventing cardiovascular events in high-risk people.

WHAT YOU SHOULD KNOW about Fat and Protein Energy

Fat has more energy per gram than protein and carbohydrate, but the body does not metabolize these nutrients in the same way. In order to be used as energy, proteins and fats must be converted to adenosine triphosphate (ATP), an energy source. The conversion of protein to ATP requires almost as much ATP as it produces. Fats, on the other hand, are easily broken down and converted to ATP. The result is an energy gain equivalent to about nine calories per gram of fat.

RELATED ARTICLE: IPay More Attention to Blood Glucose Levels

"Metabolic syndrome, the combination of high blood pressure, high blood sugar and abdominal fat, has been known for decades to be associated with a higher risk of heart attacks and mortality. We often assume, given what we have read in the literature and in the popular press, that this syndrome is necessarily associated with high levels of LDL (bad) cholesterol. Measurements of cholesterol remain the signature laboratory marker for cardiovascular risk in routine office visits to doctors for an annual clinical checkup. The studies reported here make an important 'cognitive connec-tionifor doctors and their patients to pay much more attention to blood glucose levels (also routinely measured in a thorough annual checkup) as related to cardiovascular risk, not just a marker for diabetes. In addition, these studies may help us rethink once again the constituents of a healthy diet. One word of caution: Sugar substitutes have not been demonstrated to be totally safe in themselves."

DAN G. BLAZER, MD, PhD, J.P. Gibbons professor of Psychiatry & Behavioral Sciences; Professor-Department of Community & Family Medicine, Duke
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Title Annotation:NUTRITION & FITNESS
Author:Blazer, Dan G.
Publication:Duke Medicine Health News
Date:Jan 1, 2014
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