Posts Tagged ‘insulin resistance’


Today’s post is a continuation from yesterday about nutrition, which CrossFit central emphasizes as foundational to fitness. Three main points to reiterate:

So now let’s talk about the specifics of what your body needs when exercising. First, since you’re trying to build muscle, you need protein. That’s real, not synthetic, protein, and it’s apparently easy to figure out just how much, if you really want to know, according to LiveScience:
When training, you need about a half gram of protein per pound of body weight. So a 180-pound male needs about 90 grams of protein a day. That’s the amount of protein in a cup of milk or yogurt with breakfast (8–12 grams), a can of tuna with lunch (40 grams), and a six-ounce steak with dinner (42 grams).

The emphasis on building muscle and supplying your body with enough protein is one of the reasons for the CrossFit recommendation that you “eat meat and vegetables, nuts and seeds, some fruit, little starch, and no sugar.”  The other concern prompting this recommendation is avoidance of “hyperinsulinemia.” Before getting to the definition of “hyperinsulinemia,” let me have a flashback.

I’m old enough to remember when the Atkins Diet, the first of the “let’s eat more protien” diets, came out. Before that I’d been on a lot of fad diets, including the memorable grapefruit and egg diet and one that started with a two-day fast that I almost passed out on (those were both during my teenage years, when I really didn’t need to be concerned about weight loss; I should have been focusing on fitness back then. Ah, youth!). Atkins worked for me, but many doctors were concerned about the high cholesterol levels in the diet.

I’m now convinced that whether you have  problems with cholesterol start with your genetic makeup; a good family friend who was as trim as anyone could wish for had such high cholesterol that he had a heart attack while flying his A-10 fighter. If you’re lucky, like me, you have low cholesterol even though anyone looking at you would think you’re a heart attack waiting to happen; my fit and trim hubby has to watch his. So the best thing to do is to make sure you get your cholesterol levels checked by blood test no matter your fitness level.

Even so, we all have heard by now that fish oil, olive oil and other vegetable-based oils are better for you than dairy and other animal fats. But fat is a long-burning energy resource that helps you feel full, so don’t be too stingy with it.

At any rate, Atkins was pushed aside by Covert Bailey’s Fit or Fat. Oddly, it was recommended to me by a fat doctor who was advocating an Atkins-type diet, when Bailey’s book, full of sciencey sounding justifications, advocated a higher carbohydrate, lower protein diet. The one thing Bailey said that I still agree with is that the closer the food is to its natural state, the better it is for you.

The USDA jumped on the bandwagon, but  most experts don’t care for their “new, improved pyramid.” Interestingly, the Harvard School of Public Health has, on its own pyramid, placed daily exercise and weight control as the foundational level. They do put whole grains, fats and fruit on the next level, but that’s probably consistent with CrossFit’s concern for “hyperinsulinemia.”

Now diets have come full circle: Protein Power, the Zone Diet,  the South Beach Diet and the Paleo Diet are all protein friendly and very popular. Dr. Michael R. Eades and Dr. Mary Dan Eades, Dr. Barry Sears, Dr. Arthur Agatston and Dr. Loren Cordain all have explanations that also sound scientific. CrossFit started out recommending However, ever since reading Voodoo Science>, I’ve realized I don’t know enough science to evaluate them well.

If I recall correctly, the one thing that all the books have in common is that they are based on anecdotal evidence from the respective doctors’ practices. This is generally not considered the best way to establish something as a scientific fact, so I have a tendency to take what they say with a grain of salt; on the other hand, I feel better and control my weight better with protein diets, so I’m one of the people that these diets appear to be successful for. My feeling is that, as I said in the last post, not every diet will fit everyone any more than one drug fits all.

Flashback over now; we’ll continue with hyperinsulinemia and what the heck it has to do with diet.

Hyperinsulinemia “means the amount of insulin in your blood is higher than considered normal,” according tothe Mayo Clinic. I think the real problem isn’t hyperinsulinemia but its predecessor, insulin resistance.  Back to the Mayo Clinic’s experts:

Hyperinsulinemia may be caused by insulin resistance — a condition in which your body is resistant to the effects of insulin and your pancreas tries to compensate by making more insulin. Insulin resistance may also eventually lead to the development of type 2 diabetes — when your pancreas is no longer able to secrete the large amounts of insulin required to keep the blood sugar normal.

Medicine.net’s  Ruchi Mathur, MD, FRCP(C) and Melissa Conrad Stöppler, MD have a great description of exactly what’s going in your body that makes insulin resistance an issue:

One of the actions of insulin is to cause the cells of the body, particularly the muscle and fat cells, to remove and use glucose from the blood. This is one way in which insulin controls the level of glucose in blood. Insulin has this effect on the cells by binding to insulin receptors on the surface of the cells. You can think of it as insulin “knocking” on the doors of muscle and fat cells. The cells hear the knock, open up, and let glucose in to be used by the cell. With insulin resistance, the muscles don’t hear the knock as well (they are resistant), and the pancreas is notified that it needs to make more insulin, which increases the level of insulin in the blood and causes a louder knock.

So your body can’t use the glucose it has well, and has to make more insulin, creating a cycle that just intensifies. The cycle is associated with all kinds of health problems: heart disease, Alzheimer’s, diabetes (Type 2) and various cancers.

But what causes this cycle of insulin resistance to start? It seems from searching PubMed that the details of the how it happens is up in the air, but, just as the CrossFit article on the Glycemic Index relates, the condition can be helped by the right kind of diet. Guess what? It’s one in which protein has a starring role and the carbs you eat tend to be fruits and whole grains, both of which tend to be low on the glycemic index

Glycemic index? Here’s how the University of Sydney describes it:

Not all carbohydrate foods are created equal, in fact they behave quite differently in our bodies. The glycemic index or GI describes this difference by ranking carbohydrates according to their effect on our blood glucose levels. Choosing low GI carbs — the ones that produce only small fluctuations in our blood glucose and insulin levels — is the secret to long-term health reducing your risk of heart disease and diabetes and is the key to sustainable weight loss.

It sounds like in order to feed your body well, then, you should choose from low-glycemic carbohydrates. The Glycemic Index site has a searchable database (fourth down in the left side navigation menu) so you can evaluate whether you want to eat a particular carb or not. But the GI is not the end of the story, unfortunately. Back to the Harvard School of Public Health for more:

One thing that a food’s glycemic index does not tell us is how much digestible carbohydrate it delivers. Take watermelon as an example. The sweet-tasting fruit has a very high glycemic index. But a slice of watermelon has only a small amount of carbohydrate per serving (as the name suggests, watermelon is made up mostly of water). That’s why researchers developed a related way to classify foods that takes into account both the amount of carbohydrate in the food and the impact of that carbohydrate on blood sugar levels. This measure is called the glycemic load. A food’s glycemic load is determined by multiplying its glycemic index by the amount of carbohydrate it contains. In general, a glycemic load of 20 or more is high, 11 to 19 is medium, and 10 or under is low.

NOOOO! Not math! And how do you figure out what number to plug in for the “amount of carbohydrate”? I’m still not sure, even after reading an article that purports to tell me how: “Practical use of the glycemic index.” Luckily, the Harvard guys have made a list of low glycemic load foods at The Nutrition Source

Thankfully, at least one study says that just looking at the GI helps. MedPage reports that

Among participants who completed an eight-week, low-calorie weight loss phase and then entered a maintenance phase in which they consumed diets with variations in protein content and glycemic index, weight regain was 0.93 kg higher, a statistically significant difference, in those on low-protein diets compared with those on high-protein diets.

So it’s official; most people who stay on protein plus low glycemic index foods ended up keeping off the weight they lost. As someone who has lost and regained at least a couple of people’s worth of weight, that’s good news.

Up tomorrow: The Zone vs. The Paleo.