Here is a smart belt that combines with your smartphone to track your steps and identify overeating patterns. WELT is a fitness belt that stays around your waist and counts your steps. It also measures your waist in real-time and uses data and rapid variations to identify overeating patterns.
WELT can sense waist sizes from 28 to 44 inches. It also tracks your sitting time. You can find out more on Kickstarter.