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Drink Soda? Take 12,000 Steps
September 15, 2014People who consume the sweetener fructose — which is most people nowadays — risk developing a variety of health problems. But the risk drops substantially if those people get up and move around, even if they don’t formally exercise, two new studies found.
Most of us have heard that ingesting fructose, usually in the form of high-fructose corn syrup, is unhealthy, which few experts would dispute. High-fructose corn syrup is used to sweeten many processed foods and nearly all soft drinks.
The problem with the sweetener is that, unlike sucrose, the formal name for common table sugar, fructose is metabolized primarily in the liver. There, much of the fructose is transformed into fatty acids, some of which remain in the liver, marbling that organ and contributing to nonalcoholic fatty liver disease.
The rest of the fatty acids migrate into the bloodstream, causing metabolic havoc. Past animal and human studies have linked the intake of even moderate amounts of fructose with dangerous gyrations in blood sugar levels, escalating insulin resistance, Type 2 diabetes, added fat around the middle, obesity, poor cholesterol profiles and other metabolic disruptions.
But Amy Bidwell, then a researcher at Syracuse University, noticed that few of these studies had examined interactions between physical activity and fructose. That was a critical omission, she thought, because movement and exercise change how the body utilizes fuels, including fructose.
Dr. Bidwell sought out healthy, college-aged men and women who would agree to drink soda in the pursuit of science. They were easy to find. She gathered 22.
The volunteers showed up at the university’s physiology lab for a series of baseline tests. The researchers assessed how their bodies responded to a fructose-rich meal, recording their blood sugar and insulin levels, and other measures of general and metabolic health, including cholesterol profiles and blood markers of bodily inflammation. The students also completed questionnaires about their normal diets and activity levels and subsequently wore an activity monitor for a week to gauge how much they generally moved.
Then half of the volunteers spent two weeks moving about half as much as they had before. The other 11 volunteers began moving around about twice as much as before, for a daily total of at least 12,000 steps a day, or about six miles.
After a rest period of a week, the groups switched, so that every volunteer had moved a lot and a little.
Throughout, they also consumed two fructose-rich servings of a lemon-lime soda, designed to provide 75 grams of fructose a day, which is about what an average American typically consumes. The sodas contained about 250 calories each, and the volunteers were asked to reduce their nonfructose calories by the same amount, to avoid weight gain.
After each two-week session, the volunteers returned to the lab for a repeat of the metabolic and health tests.
Their results diverged widely, depending on how much they’d moved. As one of two new studies based on the research, published in May in Medicine & Science in Sports & Exercise, reports, after two weeks of fructose loading and relative inactivity, these young, healthy volunteers displayed a notable shift in their cholesterol and health profiles. There was a significant increase in their blood concentrations of dangerous very-low-density lipoproteins, and a soaring 116-percent increase in markers of bodily inflammation.
The second study, published this month in The European Journal of Clinical Nutrition, focused on blood-sugar responses to fructose and activity, and found equally striking changes among the young people when they didn’t move much. Two weeks of extra fructose left them with clear signs of incipient insulin resistance, which is typically the first step toward Type 2 diabetes.
But in both studies, walking at least 12,000 steps a day effectively wiped out all of the disagreeable changes wrought by the extra fructose. When the young people moved more, their cholesterol and blood sugar levels remained normal, even though they were consuming plenty of fructose every day.
The lesson from these studies is not that we should blithely down huge amounts of fructose and assume that a long walk will undo all harmful effects, said Dr. Bidwell, who is now an assistant professor of exercise science at the State University of New York in Oswego. “I don’t want people to consider these results as a license to eat badly,” she added.
But the data suggests that “if you are going to regularly consume fructose,” she said, “be sure to get up and move around.”
The study did not examine how activity ameliorates some of the worst impacts of fructose, but it’s likely, Dr. Bidwell said, that the “additional muscular contractions” involved in standing and taking 12,000 steps a day produce a cascade of physiological effects that alter how the body uses fructose.
Interestingly, the young people in the study did not increase the lengths of their normal workouts to achieve the requisite step totals, and most did not formally exercise at all, Dr. Bidwell said. They parked their cars further away from stores; took stairs instead of elevators; strolled the campus; and generally “sat less, moved more,” she said. “That’s a formula for good health, in any case,” she added, “but it appears to be key,” if you’re determined to have that soda.
(Source: well.blogs.nytimes.com)