Exercise

Walking 12,000 Steps a Day Neutralizes Negative Effects of Fructose

Numerous studies have suggested even moderate amounts of fructose can wreak havoc on your health, disrupting blood sugar levels and increasing the risk of insulin resistance, type 2 diabetes, obesity, and poor cholesterol profiles.

But if you get moving—12,000 steps to be exact—you can significantly curb the damage that high fructose does, according to a new study in the European Journal of Clinical Nutrition.
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“When someone ingests a significant amount of fructose, there is an influx of fructose into the liver,” says lead study author Amy Bidwell, PhD, an assistant professor of exercise science at the State University of New York in Oswego. “The more sedentary you are… the more fats build up in the bloodstream, eventually disrupting cell-signaling from glucose homeostasis.”

That disruption leads to health problems. Conversely, increasing physical activity diminishes the deleterious effects a high-fructose diet has on glycemic control. Bidwell and her colleagues studied the interaction between physical activity and fructose in 22 healthy, college-aged men and women.

During the first 2-week session, the participants drank two fructose-rich servings of lemon-lime soda, adding an extra 75 g of fructose to their diet. Half of them maintained low physical activity (< 4,500 steps/day), while the other half increased their physical activity (> 12,000 steps/day). After a week-long rest period, the groups switched for the second 2-week session.

At baseline and after each 2-week session, the researchers performed a series of metabolic and health tests to determine how physical activity or inactivity affected their glycemic control.

“We were surprised that physical inactivity caused such a detrimental effect on glucose homeostasis, such that c-peptide values increased so much within just 2 weeks of physical activity,” Bidwell says. “This indicates that a sedentary lifestyle can make the pancreas work much harder to maintain glucose homeostasis.”

On the other hand, a more active lifestyle appeared to lessen stress on the pancreas. When participants took at least 12,000 steps a day, their cholesterol and blood sugar levels remained normal despite the extra fructose in their diet. The researchers emphasize that the findings shouldn’t encourage poor eating habits—but rather stress the importance of increasing physical activity.

To avoid deleterious health effects from fructose, Bidwell says the key is to reduce added sugar in the diet to a minimal amount. She warns consumers not to get too caught up in foods that boast “no high-fructose corn syrup” because most likely it has just been replaced with sucrose or corn syrup, which metabolically has the same effect.

“High-fructose corn syrup is not the problem; it is the large concentration of fructose, in conjunction with glucose, such as sucrose and corn syrup that is the problem,” Bidwell says. “Therefore, the more unprocessed, whole foods one can eat, the better.”

More important, she says, is to make sure patients are being active. In their study, the researchers didn’t force participants to change up their exercise routine; they simply encouraged more movement throughout the day.

“All they had to do was move more, not go to the gym and kill themselves,” Bidwell says. “Just doing 30 to 45 minutes of the recommended cardiovascular training per day is not enough. It is about being active all day—you need to take stairs, walk and talk, park farther away, do yard work, etc.”

She and her colleagues plan on studying the effects of physical inactivity on glycemic control in an overweight, obese population, as they suspect the results will be much worse.

Colleen Mullarkey

Reference

Bidwell AJ, Fairchild TJ, Wang L, Keslacy S, Kanaley JA. Effect of increased physical activity on fructose-induced glycemic response in healthy individuals. Eur J Clin Nutr. 2014 Sep;68(9):1048-54.