Two thirds of people who ordered out loud went for the cake, compared to only 38 percent of those who pressed the buttons.
Several subsequent experiments found a similar effect: People made healthier choices when they pressed buttons on vending machines, wrote their orders down, or simply grabbed the food themselves than when they ordered aloud.
Why? Using your hands when you order activates a part of your brain called the dorsolateral prefrontal cortex, which is also involved with impulse control, says study author Anne-Kathrin Klesse, Ph.D.
Source: Men’s Health