In practice, these findings mean that the benefits of sports drinks and other mid-race carbohydrates for short bouts of exercise are irrelevant as long as you don’t start out with an empty stomach and depleted fuel stores. (Pro tip: you shouldn’t.) On a more theoretical level, the results are among the strongest evidence we have that your brain is looking out for your well-being in ways that are outside your conscious control and that kick in long before you reach a point of actual physiological crisis.
