Monday, December 20, 2010

Yet More Diet Advice - Get Rid Of Carbs, Not Fat

But maybe not-so-bad advice:
"Fat is not the problem," says Dr. Walter Willett, chairman of the department of nutrition at the Harvard School of Public Health. "If Americans could eliminate sugary beverages, potatoes, white bread, pasta, white rice and sugary snacks, we would wipe out almost all the problems we have with weight and diabetes and other metabolic diseases."

...All carbohydrates (a category including sugars) convert to sugar in the blood, and the more refined the carbs are, the quicker the conversion goes. When you eat a glazed doughnut or a serving of mashed potatoes, it turns into blood sugar very quickly. To manage the blood sugar, the pancreas produces insulin, which moves sugar into cells, where it's stored as fuel in the form of glycogen.

...The first sign of insulin resistance is a condition called metabolic syndrome — a red flag that diabetes, and possibly heart disease, is just around the corner. People are said to have the syndrome when they have three or more of the following: high blood triglycerides (more than 150 mg); high blood pressure (over 135/85); central obesity (a waist circumference in men of more than 40 inches and in women, more than 35 inches); low HDL cholesterol (under 40 in men, under 50 in women); or elevated fasting glucose.

About one-fourth of adults has three or more of these symptoms.

"Put these people on a low-carb diet and they'll not only lose weight, which always helps these conditions, but their blood levels will improve," Phinney says.

..."Carbohydrates are a metabolic bully," Phinney says. "They cut in front of fat as a fuel source and insist on being burned first. What isn't burned gets stored as fat, and doesn't come out of storage as long as carbs are available. And in the average American diet, they always are."

Here's how Phinney explains it: When you cut carbs, your body first uses available glycogen as fuel. When that's gone, the body turns to fat and the pancreas gets a break. Blood sugar stabilizes, insulin levels drop, fat burns. That's why the diet works for diabetics and for weight loss.

When the body switches to burning fat instead of glycogen, it goes into a process called nutritional ketosis. If a person eats 50 or fewer grams of carbs, his body will go there, Phinney says.

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