WIFI SCALE (withings.com; $159)

WHAT IT IS: A tempered-glass scale that takes note of your weight, body fat, lean- and muscle-mass percentages, then  beams that data to your phone. 

HOW IT HELPS: It makes progress reports and charts you can monitor with a level of neuroticism usually reserved for high school wrestling coaches. For inspiration, you can set it to share your vital stats through  Facebook and Twitter, because shame is a great motivator.