After a tough run I head to the fridge and pour a tall glass of chocolate milk. Which I drink with animal cookies. Eaten head first. By the time I stretch, travel home, shower, and start to prepare (or, more accurately, wait for Husband to prepare) dinner the elapsed time is in the ninety minute range. A quick chug of chocolate milk tames my hungry stomach and feeds my glycogen resynthesis during that critical refueling window. Time and time again I’ve heard (and said) that chocolate milk is a great post-run drink, but I’ve never read the research backing up that claim. Maybe it’s all a big marketing ploy by clever folks at the Dairy Council of Canada.
In conducting my “research” (fine, googling “running + chocolate milk”) all roads led me to a 2006 study by Karp and colleagues. They compared the effects of chocolate milk, a carbohydrate replacement drink (a drink with a high carb concentration, plus protein, e.g. Endurox) and general fluid replacement (a drink with fewer carbs, but also with electrolytes, e.g. Gatorade) on a tough post-recovery workout. Given that chocolate milk has the 4:1 carbs:protein ratio found to hasten glycogen recovery and improve endurance, the authors suspected it would be a suitable option for refueling our tired muscles. Lots of investigators have studied those specially formulated sport drinks marketed to athletes, but chocolate milk had never been subject to scientific scrutiny. With the advantage of easy access and relative lower cost, it is an appealing alternative. That and it is deliciously refreshing. And chocolaty, which automatically trumps the unidentifiable Gatorade “hot pink” flavour. Because, I’ll be honest, if you don’t like chocolate there is something wrong with you. Chocolaty drinks are so awesome that I have a lame nickname for both hot and cold chocolate milk (ho-cho and co-cho, respectively). There was a need – a need! – in my life to shorten the names of my most frequently consumed drinks so that I can make my thirst demands more quickly known. “Co-cho, stat!” is much more efficient than the awkward “cold chocolate milk, stat!”.
To study chocolate milk as a recovery aid Karp and his co-authors recruited a group of willing cyclists. First the volunteer spinners cycled hard intervals until they reached a state of glycogen depletion. During the post-workout recovery they drank chocolate milk, a carb replacement drink, or a fluid replacement drink (each cyclist went through the experiment three times, trying a different drink each time). An endurance test of cycling to exhaustion followed the four hours of rest and drinking. The time to exhaustion was 54% longer after consuming chocolate milk compared to the carbohydrate replacement. The fluid replacement results were similar to the chocolate milk (49% longer to exhaustion as compared to the carbohydrate replacement drink), despite a lower carbohydrate concentration. Carbs, it seems, quickly refuel us for our next tough challenge. The authors suspect differences in the type of carbohydrate are important – not all carbs are created equal. The chocolate milk and fluid replacement drinks were similar in carbohydrate composition (glucose, fructose, sucrose), whereas the carbohydrate replacement drink contained more complex carbohydrates (maltodextrin). In the four hour recovery window only the simpler carbohydrates were completely digested, thus benefiting the second workout. The authors also speculate that drinking low-fat chocolate milk would improve performance even more, especially compared to the fluid replacement drink, because the fat in the regular chocolate milk the study riders consumed may have delayed glycogen synthesis. With low fat chocolate milk, they hypothesize, there would have been a greater endurance benefit for chocolate milk compared to fluid replacement (read: Gatorade).
Although chocolate milk did not emerge as a stand alone winner, it works at least as well as (maybe better than) commercial recovery products. I should note that this study was supported by the Dairy and Nutrition Council, Inc; but the methodology and results are sound and I don’t think the ‘milk does a body good’ conclusion was skewed to appease the funders. Whew, I’m not drinking in vain (at least not my chocolate milk drinking habit). Bottoms up.
Reference: Karp, J.R., et al. (2006). Chocolate milk as a post-exercise recovery aid. International Journal of Sport Nutrition and Exercise Metabolism, 16, pp 78-91.