by Peter J. Nebergall, Ph.D.
Almost daily we are reminded there is an epidemic of obesity in the United States. Whether you read bulletins, or follow the evidence of your own eyes, it is true: Americans are fat and getting fatter all the time.
We know why: The wrong kinds of food, and far too much of them; sedentary employment, in ever-shrinking cubicles; a "falling out of fashion" of participatory athletics (the reasons for which would make a long paper of its own), not to mention a near-total lack of organized exercise. We eat too much, of the wrong food, and we sit on our tails. So we get fatter.
We can count the cost: An estimated 250 million clinically obese people worldwide, 300,000 preventable deaths per year in the United States, and the new finding that one in three adult Americans has insulin resistance.
What is insulin resistance (IR)? The American Association of Clinical Endocrinologists defines it as a syndrome in which there is decreased tissue sensitivity to the action of insulin, leading to a compensatory increase in insulin secretion. Where once this condition was seen merely as a precursor (in about 50% of cases) to type 2 diabetes, it is now known to increase risk of serious, primarily cardiac, ramifications.
What causes insulin resistance? We're not exactly sure. We know there are two components: Genetic and Environmental. We know that, like type 2 diabetes, IR runs in families. We know that certain ethnicities have a higher proportion (though this may reflect environment, not genetics at all - see the Pima study), and we know that increasing age (read: decreasing activity) increases the risk. The second half of IR, the part we understand better, has to do with obesity. Although all obese people do not have insulin resistance, or type 2 diabetes, if you are genetically predisposed to IR (if you "carry the trait"), and you let your weight climb up into the "obese" range (Body Mass Index >= 25), insulin resistance will express, to a greater or lesser degree. And you don't want the consequences.
Fortunately, the converse is true: If you are overweight and insulin resistant, and you lose weight, reducing your body mass index, you can cut your insulin resistance, and the risks that go with it - including the risk of developing type 2 diabetes. If you already have type 2, the same weight loss can reduce its severity - perhaps into insignificance.
We haven't changed our genetic make-up much in the last few centuries, but IR has rocketed 61% in the last decade - congruent with the big rise in type 2 diabetes. Possible clues come from the Pima Study.
The Pima are a Native tribe of the American Southwest. The tribal area crosses the Rio Grande; there are Pimas on both sides of the border. Several years ago, concerned that their people had the highest percentage of diabetics anywhere (approximately 51 percent of the tribe, on the U.S. side, had type 2), the tribe asked researchers to come and see if they could explain why, and describe what they should be doing different. Results were startling.
On the American side, a cash economy had replaced the old ways. There was a lot of inactivity; people cooked high-carbohydrate "white man's food," and watched a lot of television. A majority of American Pimas had overt type 2. Even more were insulin-resistant.
On the Mexican side, Pimas tended to follow their traditional subsistence-farming lifestyle. They tilled their fields with animals, and ate the fresh produce they grew themselves. What was the percentage of diabetes for Pimas on the Mexican side? About 5 percent - less than their Gringo neighbors! Remembering that these people were genetically identical to the U.S. Pimas, the differences were entirely attributable to lifestyle - to how they worked and what they ate.
How do you work? What do you eat? Odds are your work is pretty sedentary -- more like the U.S. Pimas than their Mexican brethren. Odds are you watch more and move less than you used to ... and ever notice how the clothing adverts all assume you're getting heavier than you used to be?
What about food? There's a reason for the term "junk food" (and Ralph Nader recently called the double cheeseburger "a weapon of mass destruction") - it's not very good for you. The sedentary adult male working in his cubicle requires 1800 calories a day, to maintain. A double cheeseburger is 600-plus calories, and the "deluxe" burgers can run over 1000 calories. A 40-ounce drink can be 600 more calories, and "don't forget the fries!" You're over your allotment - and that was just lunch!
For dinner, do you have a 12-ounce steak? Fried chicken, chicken-fried steak, pizza with everything? For breakfast, pancakes, bacon, sausage, scrambled eggs ... Count the calories, just for fun, and you'll see just what is "over easy" -- it's your calorie count.
Dieting, no matter how successfully, cannot remove the genetic predisposition to insulin resistance -- but if you remember that the excess food has to go somewhere, and that what you don't eat won't raise your IR or your blood sugars -- then you're on the way.
There are tests to diagnose insulin resistance, and medications to reduce its severity. Still, the best approach is the one advocated by Hippocrates the Physician, thousands of years ago: a healthy lifestyle. You can prevent or reduce so much of the impact of insulin resistance, by yourself, by increasing your activity, and eating wisely. Good luck.