Raisins for runners just as good as commercial sports food
Runners who want an energy boost when training or at a match can benefit more from a few small boxes of raisins than from expensive products available at the sports shop. Sports scientists at the University of California in Davis have good news for price-conscious – and health-conscious - runners.
Raisins versus commercial sports food
In 2007 researchers at San Diego State University did a study showing that raisins had just as positive an effect on the achievements of cyclists as did sports gels. That was surprising news, since raisins have a lower glycemic index than gels. Evidently, fast carbohydrates, which enter the circulatory system quickly and drive up the concentration of insulin, aren't as good for endurance athletes as producers of sports foods would have us believe.
Sports scientists at the University of California repeated the 2007 study, but now with runners instead of cyclists and with Clif Shot Bloks instead of a sports gel.
The researchers had 11 trained runners run for 3 x 80 minutes on a treadmill at 75% of their maximum oxygen intake. Immediately following this, the runners had to run 5 km as quickly as possible.
When the experiment began and after every 20 min, the subjects were given either a bit of water, or 3 Clif Shot Bloks, or 30 gr of raisins. Both the portions of Clif Shot Bloks and the raisins supplied 100 kcal and 24 gr of carbohydrates. Half of the carbs in the raisins consisted of glucose and the other half of fructose; the Clif Shot Bloks contained maltotriose [a trisaccharide with a glycemic index of 67], maltose [the super-fast absorbable disaccharide in beer with a glycemic index of 105], glucose and fructose.
The raisins [Raisin] resulted in the fastest achievements during the 5-km run, but the difference with the times noted after taking Clif Shot Bloks [Chews] wasn't statistically significant. Both raisins and Clif Shot Bloks resulted in better achievements and a slightly higher heart rate [HR].
According to the researchers, after eating raisins, you burn more body fat and fewer carbohydrates than after eating Clif Shot Bloks.
During the 80-min run, the concentration of creatine kinase in the blood increased a tiny bit more after eating raisins than after eating the Clif Shot Bloks, which indicates muscle damage. The researchers have yet been unable to discover the cause of this. The subjects, however, didn't notice any difference. They reported having just as much muscle pain after the test with Clif Shot Bloks as after the test with raisins.
"Ingestion of a natural food product, raisins, had similar performance effects as a commercial sports product in chews and both products improved running time trial performance over water only", the researchers concluded.
This will certainly make their sponsor happy: the California Raisin Marketing Board.
J Int Soc Sports Nutr. 2012 Jun 15;9(1):27.
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