Metabolic Syndrome # 5 Here Comes the Proof: It’s the Carbs!
Competency # 20 Lifestyles of the Long-lived
Reference: Reference: Am J Clin Nutrition. Feb, 2008:87:339 Halton and Hu
From the Harvard School of Public Health and the Nurses’ Health Study
Well, we’ve set the table. Insulin is the prime enemy in metabolic syndrome and metabolic syndrome is the mess most of us are in. Insulin resistance is the fundamental cause of metabolic syndrome. The story we’ve told over the last two months has been the conundrum we are in with the advice to eat a low fat diet, while intuitively recognizing that a low fat diet, the current recommendation of the American Diabetes Association, ends up being a high carbohydrate diet by default. And that diet makes metabolic syndrome worse. What’s a gal/guy to do? Is eating a low fat diet the right diet? Low fat/high carbs, officially sanctioned now for 30 years has correlated with all of us gaining weight by the truckload. The world seems upside down and backwards. Is there any evidence to suggest we should do something else?
YES! THIS MONTH! Frank Hu is one of the prime leaders of the Nurses’ Health Study and his group has just published what I believe to be a major study looking at a prospective view of 85,059 nurses and their consumption of carbs. Head to head, low fat (AKA, higher carb) versus low carb diets (AKA: higher protein and fat). They now report a 20-year follow-up comparison. This isn’t a short-term study. Nor is it small. So it carries some weight. They looked for the onset of adult onset diabetes with one diet or the other. What they found was that the low carb diet DID NOT increase the risk of diabetes. In fact, diets high in vegetable protein and fat “may modestly reduce the risk of diabetes”.
Metabolic syndrome is actually most accurately described as insulin resistance as the core problem. Diabetes shows up only after many years of insulin resistance. Catching the metabolic process early on is the best and simplest way to prevent diabetes. All the other components of metabolic syndrome can be interpreted as reflections of the core problem. High blood pressure may be driven by elevated insulin levels as much as any other cause. Elevated lipids may have all the same cause. Obesity is clearly correlated. The problem is that we can’t measure insulin resistance easily. It’s much too complicated to measure. It’s easy to measure your waist, your blood pressure and your blood fats. (Did you know that cardiovascular risk starts with a blood glucose of 83? Not 110, the definition of borderline diabetes. So risk for a heart attack starts with insulin resistance at a level of 83, not when frank diabetes shows up.)
The story probably revolves around the type and quantity of the carbs we eat. Glycemic load is the concept to put it all together, and Hu’s study confirms that. Glycemic load is the “area under the curve” of glucose rise in response to foods. It takes into account the type of carbs and the total amount you eat. So, you can cause as much trouble eating huge amounts of low glycemic foods as you can be eating small amounts of pure sugar. This study found that high glycemic diets “strongly correlated” with the risk and onset of diabetes. So, eating below the “Insulin Line” works. (You start to secrete more insulin with foods over a glycemic index of 55. But you will still secrete insulin if you eat pounds of low glycemic carbs or a higher glycemic load.) High protein, high fat results in less diabetes. Low fat doesn’t work. The world has been upside down. Let’s put it right.
WWW. What will work for me? My fasting blood sugar was 99 this year. That’s over 83. So, I’m in this mess too. It’s the carbs, and the type of carbs. Benefit comes in the form of vegetable sources of fat and protein. More olives, nuts, avocados, beans, peas, lentils, soy! Carbs should look like pears and apples, broccoli, carrots and beans: whole foods. Eat less pasta, rice, potatoes, bread, donuts and brownies. It’s eating “Below the Insulin Line”. 85,000 nurses for 20 years is pretty good proof. I’m still grieving the thought that those donuts have gotta go…