Matthew Kadey, MS, RD November 18, 2011 TWEET COMMENTS 1

Sugar Shock

Before you chug down another sports drink, learn the not-so-sweet truth about sugar

Are you high? If you're like most U.S. citizens the answer is likely yes. According to conservative USDA estimates, ...

Photo by Duane Raleigh

Are you high? If you're like most U.S. citizens the answer is likely yes. According to conservative USDA estimates, on average, Americans consume 22 teaspoons of "added sugars" each day, or 355 additional calories, more than double what is recommended by the American Heart Association. Sweetener consumption has jumped by 19 percent since 1970 to a hefty 140 pounds a year for every man, women and child. And the gel-sports-drink-energy-bar-loving trail runner is far from exempt in the sugar onslaught.

Sugar and Exercise

Research shows that wolfing down sugar-laden foods or drinks with a high glycemic index (GI), like white bread, ice cream or high-sugar energy-bars about an hour before a run may cause you to tire more quickly. A rapid spike in blood sugar before exercise can force your pancreas to pump out large amounts of insulin, which results in a sudden, performance-zapping drop in blood sugar during exercise.

Case in point: Researchers in a recent issue of the Journal of Science and Medicine in Sport found that cyclists rode significantly faster 45 minutes after eating a low GI pre-race meal than a high GI one. The low GI meal led to an increase in the availability of carbohydrates and a greater carbohydrate oxidation throughout the time trial, which likely helped sustain increased energy production.

However, a raft of research papers shows that sugar-spiked foods can help you train harder and longer on the trail. Why? One word: Glycogen. Glycogen is sugar in storage form. It is your body's most important and efficient source of energy during high-intensity exercise.

"Once muscle glycogen levels sink too low, fatigue sets in and you start to feel like you're running through Jello-O," says Tara Gidus, RD, owner of Tara Gidus Nutrition Consulting in Orlando, Florida. "During long bouts of exercise, eating rapidly-digested sugars such as those found in gels or sports drinks can help preserve stored muscle glycogen and keep you working harder for longer."

If running for more than 60 minutes, Gidus suggests consuming 30 to 60 grams of simple carbohydrates for each hour of activity. If exercising for an hour or less, water is all you need.


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