We see athletes do this all the time: fill their mouths with Gatorade, swish it around, then spit it out. It's not just something "cool" to do, but it actually helps to give them energy and boost performance. When you put something into your mouth, it sends signals to the rest of your body that there's something on the way to your digestive tract. Your body basically fires up the ol' food processing machine, ready to absorb nutrients and calories. [caption id="" align="aligncenter" width="575"] Source: sfdiamondgirl.mlblogs.com[/caption] If you were to swallow the Gatorade, you would be giving your body the energy to burn. Spitting it out, however, is like a "bait and switch". It tells your body that energy is on its way, so it is all fired up and ready to go. Spitting it out stops you from consuming the calories and sugar that would affect your blood glucose levels, but you still get all the energy you need. A 2009 British study confirmed this. Bikes who used this trick boosted performance by up to 3% over those who didn't.