When you’re face to face with the free donuts in the break room, resist by clenching your fists. Doing that for just a few seconds can give you a surge of willpower. That’s according to the Journal of Consumer Research. When study participants did that, more often than not, they chose a healthier snack. Why does it work? Because we naturally tense up when we’re faced with something challenging. So it sends a signal to the brain that we’re faced with a tough task – and the brain responds by giving us a surge of mental energy. So clench your fists to resist temptation.