Okay to eat sugar-filled foods before sporting activities?

Originally Published: April 4, 2003
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Dear Alice,

Is eating glucose based food good for you before sports?

Curious

Dear Curious,

Some researchers in the 1970s found that when athletes drank a sugary beverage 30 minutes before exercise, they became tired quickly. That's because they found that these simple sugars caused a large surge in insulin (the hormone that helps get blood sugar into muscles). The insulin then caused a sharp decrease in blood sugar, as it moved the glucose into the muscle. At the same time the blood glucose was being lowered, the insulin also prevented the athletes from being able to use fat for energy. This caused the athletes to use up the carbohydrate that was stored in their muscles (glycogen) rather quickly. This all sounds reasonable, however, no other studies have been able to repeat the same findings.

The prevailing advice today is to take any simple sugars 60 minutes prior to exercise. That way, it leaves sufficient time for one's body to re-establish hormonal balance. The degree to which blood sugar increases and decreases depends on a variety of factors — our genes, the form of carbohydrate, and the food it may be contained in, in addition to a variety of other factors. If you compete on a team or individual sport, it's recommended that you test this out during a practice, rather than before a game or meet. If you're a recreational exerciser, experimenting with the timing of different foods and beverages may help you to determine what works for you.

Alice