To Eat What You Want, Keep Your Body in Gear
Thursday, August 28th, 2008
Source: Foot.com
Publication date: 20080828
Wolfgram, a St. Louis psychiatrist and good friend of mine, has been competing in marathons and Ironman triathlons for 30 years.
Schmidt, a bed-and-breakfast manager in Illinois, is obese and has Type II diabetes.
Wolfgram is 75.
Schmidt is 52.
The differences in their diets and their overall health illustrate a fundamental truth about the human body: We’re designed to move, especially if we want to live a long, healthy life without severe dietary restrictions.
Exercise lowers blood sugar levels, insulin levels, blood pressure and triglycerides. Exercise raises HDL levels, the good cholesterol that seems to protect against heart attacks. Add all this up and the message is clear: We must be fit to eat.
Now comes Edward Weiss, assistant professor in nutrition and dietetics at St. Louis University, with further evidence to support this. Weiss recently studied how exercise affects flow-mediated dilation, the rate at which blood vessels contract and dilate. Previous studies have shown that people with low rates are more likely to develop heart disease within five years than those with normal levels, he said. Sugary foods can cause flow-mediated dilation to plummet, and Weiss wanted to see if exercise would offset that negative effect.
The short answer, he says, is yes.
Weiss began his study by getting the baseline measurement of the flow-mediated dilation of 13 study subjects who had not exercised for a while. Then he had them drink a 20-ounce soda and eat a candy bar — “a typical American snack.”
When he measured their rates again, Weiss found they’d decreased substantially.
A few weeks later, he had the 13 participants exercise for one hour, at about 70 percent of their maximum heart rate. Weiss says most people in their 50s and 60s can reach maximum heart rate with a brisk walk. Seventeen hours later, he had them drink a 20-ounce soda and eat a candy bar and measured their flow-mediated dilation again.
Weiss found that when their rate deteriorated to its lowest level this time, it wasn’t much lower than their baseline rate, which was taken without exercise and pre-snack.
“From that perspective, exercise prevented the negative effects of the sugar,” he says. Weiss chose to wait 17 hours between the exercise and snack, figuring that people who exercise regularly are always within a day or two of their last workout, which will always be providing some protection against the unhealthful foods they eat.
This doesn’t give avid exercisers a free pass to eat all the high-calorie, high-fat, sugary foods they can shovel in. (Unless, of course, you’re a gold medalist named Michael Phelps.) And it doesn’t mean that every couch potato with a poor diet is going to get Type II diabetes or drop dead of heart disease at age 57. Some people have good genes.
But Weiss points out that sedentary people who eat high-fat, high-calorie diets run a higher risk of developing heart disease, diabetes and cancer than their contemporaries who exercise regularly.
He’s heard those people justify their diets and lack of physical activity by calling it a “quality of life” issue. They like to joke that avid exercisers don’t really live longer, it just seems that way because they’re exercising so much.
“But you look at an obese person, and their knees are bad and they can barely move and you think, ‘Is this good quality of life?’” Weiss said.
The same goes for food. Suddenly, the chubby couch potato hits 55 and can’t eat half the foods he did 10 years before without ballooning or putting his health at risk.
“There’s data that show that lean, healthy endurance athletes on average eat 50 percent more calories than obese people,” Weiss says. “To optimize health it should be healthy food, such as whole grains, fresh fruits and vegetables.”
And maybe, when the doctor isn’t looking, an apple fritter.
cbillhartz@post-dispatch.com — 314-340-8114
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