Ask people what they ate yesterday, and they will get it wrong. Not usually on purpose. Memory is bad, portions are hard to estimate, and snacks disappear from recollection entirely. Nearly everything public health knows about how people eat rests on that shaky foundation.
A team at Northwestern University has spent years building an alternative: a necklace that watches. Their system, HabitSense, combines a thermal sensor array, a small camera, and motion sensors, runs machine learning models on the device itself, and pings a paired smartwatch when it thinks the wearer is eating or smoking.
