Fast food for recovery?
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I would like to discuss a recent research article because I think it makes a good point. I am not sure if popular press has picked up this research article yet, but I am sure it will eventually and I do not think the message will be what it should be. Researchers from the University of Montana did a study on post-exercise feeding and glycogen recovery. Even though this hardly sounds novel, this study had a twist – the researchers pitted fast food against a sports supplement. What did the researchers find? I’ll explain that in further detail.
The study used a nice design in which subjects completed a glycogen depleting exercise bout on a bike followed by a 4-hour recovery. The subjects received food (sports supplement or fast food) immediately after the bout of exercise and again 2 hrs into the recovery. After the four hours of recovery, the subjects performed a 20 km TT as fast as possible. By this design the authors were able to assess the rate of muscle glycogen recovery (with multiple muscle biopsies) and subsequent exercise performance. The findings indicated that eating fast food replenished glycogen just as quickly as a sports supplement and there was no difference in performance between the two groups. In other words, the fast food “supplement” worked just as well as the sports supplement.
I know the laboratory where this research was done and I am friends with two of the researchers. When I saw this article, I imagined the conversation that lead to the designing of the study. The researchers are very good athletes themselves, and I imagine that one of them was trying to make a point to the other. Of course this is just speculation on my part and I am yet to ask them if that is the case. Because they are good researchers, the study was well designed with a critical design element – the fast food and sports supplement were matched for both macronutrient content and total calories. The conclusion of the study stated that, “short-term food options to initiate glycogen resynthesis can include dietary options not typically marketed as sports nutrition products such as fast food menu items.” I have always believed this to be true and often recommend real food during recovery. However, to broadly apply this strategy to include fast food might be unwise. An important message that I must stress here is that there is a big difference between eating for sports performance and eating for health.
Notice that the authors state “short-term food options” in their conclusion. I think this is on purpose. I am not sure anyone would recommend this post-exercise fueling as a long-term strategy. There are several other factors one should consider. First, the feeding in this study was controlled to a specific calorie content. Because fast food is typically calorie dense, it is reasonable to assume that what is provided as a “meal” from a fast food establishment can often well exceed ones needed caloric intake. Over time, excess caloric intake leads to energy storage. Second, there is a whole host of negative consequences of the high fat and high saturated fat content typical of fast food. For example, oxidative stress and inflammatory responses are expected over time for this eating pattern. These additional stresses lead to poor adaptive responses (e.g. to exercise) and poor health outcomes. Third, it is important to consider the micronutrients that are missing because of a repeated pattern of eating fast food. Although fast food is known to be energy dense, it is not necessarily known to be nutrient dense. There are many more examples beyond these three.
To make the point again, what is good for sports performance should not necessarily be equated to what is healthy. There are many instances where what is helpful for sports performance is not good for long-term health outcomes. In a sense, exercise helps buffer some of these negatives. In addition, just because someone is a high performing athlete, it does not mean they are exceptionally healthy. We know that the extreme conditions a high performance athlete puts him/herself under is sometimes decidedly unhealthy. All of this is to say that one needs to be careful when extrapolating outcomes related to exercise performance to general health.
Last, I do not want the take-home message from this article to be that I believe that sports supplements are superior for performance or health outcomes. I do not believe that at all. I fall firmly on the side that real food is an effective strategy and I have said so in this column before. Although sports supplements and fast food CAN help one recover their glycogen and perform well in a subsequent exercise bout, it does not mean that they SHOULD be used – at least not as a regular strategy.
Full abstract of original article:
Cramer MJ, Dumke CL, Hailes WS, Cuddy JS, Ruby BC. Int J Sport Nutr Exerc Metab. 2015 Mar 26. Post-exercise Glycogen Recovery and Exercise Performance is Not Significantly Different Between Fast Food and Sport Supplements.
Abstract
A variety of dietary choices are marketed to enhance glycogen recovery after physical activity. Past research informs recommendations regarding the timing, dose, and nutrient compositions to facilitate glycogen recovery. This study examined the effects of isoenergetic sport supplements (SS) vs. fast food (FF) on glycogen recovery and exercise performance. Eleven males completed two experimental trials in a randomized, counterbalanced order. Each trial included a 90-minute glycogen depletion ride followed by a 4-hour recovery period. Absolute amounts of macronutrients (1.54 ± 0.27 g·kg-1 carbohydrate, 0.24 ± 0.04 g·kg fat-1, and 0.18 ± 0.03g·kg protein-1) as either SS or FF were provided at 0 and 2 hours. Muscle biopsies were collected from the vastus lateralis at 0 and 4 hours post exercise. Blood samples were analyzed at 0, 30, 60, 120, 150, 180, and 240 minutes post exercise for insulin and glucose, with blood lipids analyzed at 0 and 240 minutes. A 20k time-trial (TT) was completed following the final muscle biopsy. There were no differences in the blood glucose and insulin responses. Similarly, rates of glycogen recovery were not different across the diets (6.9 ± 1.7 and 7.9 ± 2.4 mmol·kg wet weight- 1·hr-1 for SS and FF, respectively). There was also no difference across the diets for TT performance (34.1 ± 1.8 and 34.3 ± 1.7 minutes for SS and FF, respectively. These data indicate that short-term food options to initiate glycogen resynthesis can include dietary options not typically marketed as sports nutrition products such as fast food menu items.