Medicine Nutrition Sports Medicine

Quick Carbs: Dark Side of Fructose (repost 2007)

A variety of conflicting studies and articles are coming out regarding high glycemic foods in performance. What impact do they have and what conflicting studies show is a future topic for us. Fructose is not considered an optimal source of carbs and the sports drinks and gels you use should be examined to make sure that fructose is not high on the ingredients list.

It is lower down on the listing of ingredients in Gatorade, but it is number 2, after water on Powerade (Matrix Reloaded). Powerade is said to be the official drink of the US Olympics. Perhaps it is time to revisit that choice.

At the same time this is under discussion Abel Pharmboy at Terrasig has a fine post up entitled “The Questionable Dark Side of Fructose“. He notes that the consumption of fructose has been suggested to be one of the possible causes of obesity and metabolic syndrome. In conjunction with this he links to an article at Medscape which notes the atherogenic profile of fructose vs. glucose.

The question that plagues this research area is whether the growing (pun intended) obesity epidemic since the 1970s is due to HFCS or simply our overall increase in consumption of all sweetened beverages. I remember when Coke used to come in 8 oz bottles; now you can buy a 44 oz Big Gulp, or at least an average 20 oz bottle. The HFCS issue is also entangled with public aversion to genetically modified foods, including corn, and the fact that large corn-processing companies benefit from subsidies unavailable to conventional sugar cane producers.

Regardless of whether HFCS is more problematic than glucose or sucrose, the only sure way to reduce one’s risk of weight gain due to HFCS is to replace sweetened beverages with good old water.

quote from: Terra Sigillata – Abel Pharmboy

It is definitely up to you to carefully determine what should be in your sports replacement drinks and gels. For long distance running, it is possible that you will benefit from electrolyte replacement. Avoidance of hyponatremia in events of more than a few hours is important. Weighing in and monitoring your body weight over the course of a marathon or ultramarathon may help you reach the proper balance of fluid replaement vs. over or under hydration. During training for long distance events you can weigh yourself after an hour of exercise, if you are in good health, and your doctor clears this, to get an idea of how much fluid you need to replace per hour. At the end of your long runs, with a weigh in before and a weigh in after, you can see how close you are to meeting your goal of proper fluid replacement.