Tuesday, December 21, 2010

(Updated) A Reversal On Carbs

From the L.A. Times.

"...a growing number of top nutritional scientists blame excessive carbohydrates — not fat — for America's ills. They say cutting carbohydrates is the key to reversing obesity, heart disease, Type 2 diabetes and hypertension."


"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."

It's a confusing message. For years we've been fed the line that eating fat would make us fat and lead to chronic illnesses. "Dietary fat used to be public enemy No. 1," says Dr. Edward Saltzman, associate professor of nutrition and medicine at Tufts University. "Now a growing and convincing body of science is pointing the finger at carbs, especially those containing refined flour and sugar."

Americans, on average, eat 250 to 300 grams of carbs a day, accounting for about 55% of their caloric intake. The most conservative recommendations say they should eat half that amount. Consumption of carbohydrates has increased over the years with the help of a 30-year-old, government-mandated message to cut fat."

So why does the Food Guide Pyramid tell us to eat 6-11 servings a day of carbs in the form of whole grains? They break down into sugar just like simple carbs, only slower! I believe that 1-2 servings/day of whole grains would suffice, but I'm no doctor.

"To understand what's behind the upheaval takes some basic understanding of food and metabolism.

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.

If you have a perfectly healthy metabolism, the system works beautifully, says Dr. Stephen Phinney, a nutritional biochemist and an emeritus professor of UC Davis who has studied carbohydrates for 30 years. "However, over time, as our bodies get tired of processing high loads of carbs, which evolution didn't prepare us for … how the body responds to insulin can change," he says.

When cells become more resistant to those insulin instructions, the pancreas needs to make more insulin to push the same amount of glucose into cells. As people become insulin resistant, carbs become a bigger challenge for the body. When the pancreas gets exhausted and can't produce enough insulin to keep up with the glucose in the blood, diabetes develops.

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."


"The take-home message from this study and others like it is that — contrary to what many expect — dietary fat intake is not directly related to blood fat. Rather, the amount of carbohydrates in the diet appears to be a potent contributor.

"The good news," adds Willett, "is that based on what we know, almost everyone can avoid Type 2 diabetes. Avoiding unhealthy carbohydrates is an important part of that solution." For those who are newly diagnosed, he adds, a low-carb diet can take the load off the pancreas before it gets too damaged and improve the condition — reducing or averting the need for insulin or other diabetes meds."


""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. (Nutritional ketosis isn't to be confused with ketoacidosis, a dangerous condition that can occur in diabetics.)

Beyond the fat-burning effects of ketosis, people lose weight on low-carb diets because fat and protein increase satisfaction and reduce appetite. On the flip side, simple carbs cause an insulin surge, which triggers a blood sugar drop, which makes you hungry again."

But when you counteract this with a high-protein diet, like the first stages of the Atkins diet, you put your kidneys at risk.

"Though the movement to cap carbs is growing, not all nutritional scientists have fully embraced it. Dr. Ronald Krauss, senior scientist at Children's Hospital Oakland Research Institute and founder and past chair of the American Heart Assn.'s Council on Nutrition, Physical Activity and Metabolism, says that while he fundamentally agrees with those advocating fewer dietary carbs, he doesn't like to demonize one food group.

That said, he adds, those who eat too many calories tend to overconsume carbohydrates, particularly refined carbohydrates and sugars. "It can be extremely valuable to limit carbohydrate intake and substitute protein and fat. I am glad to see so many people in the medical community getting on board. But in general I don't recommend extreme dietary measures for promoting health."


"As nutrition scientists try to find the ideal for the future, others look to history and evolution for answers. One way to put our diet in perspective is to imagine the face of a clock with 24 hours on it. Each hour represents 100,000 years that humans have been on the Earth.

On this clock, the advent of agriculture and refined grains would have appeared at about 11:54 p.m. (23 hours and 54 minutes into the day). Before that, humans were hunters and gatherers, eating animals and plants off the land. Agriculture allowed for the mass production of crops such as wheat and corn, and refineries transformed whole grains into refined flour and created processed sugar."

My answer to all this health advice topsy-turvy. I'm already battling diabetes, heart disease, and obesity in the family, and have already been to the best doctor around for this stuff: a nutritionist. Doctors receive only 8 hours of nutritional classroom study, and it's quickly forgotten in the race to specialize--otherwise, there's no money to be made for paying back exorbitant student loans. You want the TRUE nutritional dirt on what you should eat? Go see a nutritionist, even if you have to pay out of pocket for it. My health care reform page is a collection of what I learned while at the nutritionist office, so I tried to save you some time and money, and I just might end up saving your life in the process.

UPDATE: an article about sugar and cancer. Also, a cookbook from 1976 mentions the low use of sugar because it causes heart disease.


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