Here is a smart belt that stays around your waist and uses sensors to count your steps and monitor rapid variations in your waist size to detect overeating. The device can be worn like a normal belt and pairs with your smartphone using Bluetooth 4.1. The battery life lasts 20+ days.
This belt can monitor your waist size from 28 to 44 inches. It counts your steps using an embedded pedometer. It also tracks your inactivity time. The data is made available on your phone. Expected to ship in January.