Originally written for Switch4Good
Why is chocolate milk so ingrained in sports culture? Milk has science on its side. The industry pays for studies that are designed to yield positive results, and these (often barely statistically significant) results are turned into national advertising campaigns to convince consumers to buy more milk. The Built with Chocolate Milk campaign cites this study to uphold milk as the optimal post-workout recovery beverage. This particular study claims that milk hydrates better than water or sports drinks, but when we looked deeper at the actual methodology and the numbers, we found the industry’s interpretation to be extremely flawed.
Funded by Dairy
Funded by the National Dairy Council of Ireland, the researchers were pressured to achieve results that favored dairy. Most industry-funded researchers accomplish this by designing the study in a way that they are confident will benefit a particular product. The science is true, but the methodology is rigged. In this study, researchers assured favorable milk outcomes by designing a highly controlled scenario not applicable to real life.
The 7 Participants
First, it is necessary to look at the participants. The Built with Chocolate Milk campaign claims chocolate milk is essential for all athletes—no matter their race or gender. However, only seven white, lactose-persistent, Irish men with an average age of 26 years were chosen for this study. The lack of diversity is laughable, and this minuscule number of participants is not significant enough to yield conclusive results—especially not for a diverse population.
These seven participants underwent two trials of dehydration and rehydration. The participants fasted (no food or water) for five hours then exercised in a warm environment until they had lost two percent of their body mass. Then, over the course of five hours, participants rehydrated with either one percent milk, Powerade, or water until they had consumed 150 percent of their body mass loss.
Researchers found that the milk drinkers had a lower urine output, higher net fluid balance, and higher plasma osmolality. These markers informed the conclusion that milk hydrates better than water or Powerade. However, what these results really show is that, most likely, milk stays in the body longer and causes water retention. For the vast majority of people, water retention is not a desired trait.
Further, hydration markers such as sodium level and CTproAVP remained constant amongst all three beverages. These factors may present a clearer picture of one’s state of hydration—not water retention—and yet milk had no superior effect in these two areas.
Another factor not addressed in the conclusion is the fact that the milk drinkers restored their caloric deficit by 106 percent, meaning they overconsumed what they needed. If people exercise to lose or maintain their weight, drinking milk (or chocolate milk) post-workout could derail the work they just put in.
Finally, the scenario is simply not applicable to real life. Most people do not fast for five hours post-workout. There is no way to tell how hydration would be affected with food. Also, most people are not 26-year-old Irish men. The results are for a very select group of individuals and cannot be applied to an entire population.
Milk has science on its side, but that doesn’t mean we should trust it. Unfortunately, studies can be manipulated and the industry can pick and choose what results to feature. Milk is not an optimal exercise recovery drink, and it doesn’t do a body good. Find out what the ads aren’t telling you here.