In "Jump Start," human guinea pig A.J. Jacobs tests out the best motivation tricks, revealing the secrets to achieving your goals.

Motivational Hack: The Toothbrush Diet

Brush your teeth after dinner to prevent unwanted snacking.

The Explanation

I learned this trick from my friend Gretchen Rubin, author of the best-selling book The Happiness Project. Gretchen is working on a book about habits, and suggests post-dinner brushing at about 8:30 p.m. She finds it an effective stop-eating hack. As she puts it, “My mouth feels the signal of ‘done for the day.’ Many years of nightly brushing have made me connect the experience of toothpaste with the beginning of bedtime.” 

The Test

After my dinner of black beans and guac, I washed the dishes... then washed my mouth. I stood in front of the mirror and brushed my teeth with my Tom’s cinnamon toothpaste (using the "modified bass" technique, as suggested by my dentist). Immediately after, I felt refreshed and had less of an urge to eat a post-meal pack of M&Ms. An hour later, however, I broke down and had a bowl of sugary cereal.

The next night, I switched tactics: I tried Tom’s peppermint toothpaste. I’m not a big fan of minty toothpastes, but I admit they give you that tingly feeling. And the peppermint turned out to be a more effective snack repellent. I felt like my mouth was a pair of new white sneakers, and I didn’t want to step in the mud by opening that fridge. 

I decided to push this tactic to its limit. Over the next week, I brushed after lunch as well. And then I started to brush after every trip to the bathroom. Not an extensive brushing; just a few swipes with the bristles to get that taste of mint (a mere six seconds).

In between all the brushing, I still snacked -- but the tactic reduced my mindless eating by as much as 40 percent. Never underestimate the psychological power of cleanliness. Just as tidying my desk makes me feel better and want to be more productive, brushing my teeth makes me behave more healthily.

The Grade: B+

A good way to make your dentist proud -- and to trim calories from your diet. 

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