Here’s a little test for you. Picture two beverage glasses, each containing a drink with identical nutritional content. Not a sugar molecule’s worth of difference. Indeed, the only thing differentiating these two beverages is color. One is clear, the other pink.

True or false: The pink drink will supercharge your workout and increase exercise performance.

On its face, that might not make sense. But the answer is true.

British researchers conducted what they believe is the first scientific investigation of the effect of drink color on exercise performance. They asked study participants to run on a treadmill for half an hour at a self-regulated pace in two sessions. The goal was to keep up a steady rate of exertion.

In one workout, volunteers rinsed their mouths with a clear drink that was artificially sweetened and low in calories. In a second, they rinsed with a drink containing a smidge of pink food dye that was otherwise identical to the first.

Why pink? Why not purple or red or taxi-cab yellow? Well, scientists figured pink is associated with perceived sweetness. As such, that increases the expectation of receiving energy-boosting sugar and carbohydrates — even if the body was really getting none of it. Previous research had shown rinsing the mouth with real carbs pushes the body to better performance.

Guess what? Participants who partook of the pink drink ran an average of 695 feet farther while their mean speed increased about 4% compared with when they rinsed with a clear liquid.

Not only that, but the pink drinkers also found exercise more enjoyable.

So next time you head to the gym, think pink drink, and let the placebo effect work its magic.