Wearable bio-logging used to "fight fat"

Fight against fat goes high-tech with new devices (AP):

The fight against fat is going high-tech. To get an inside look at eating and exercise habits, scientists are developing wearable wireless sensors to monitor overweight and obese people as they go about their daily lives.

Understanding food is still manual, but a necklace-cam sounds cool:

University of Pittsburgh engineer Mingui Sun has developed a necklace equipped with a video camera that records where a person goes and what he or she eats. Before a researcher sees the data, it's filtered by a computer that blurs out other people's faces.

The device is not smart enough to know whether the wearer ate a Big Mac or tofu. So a researcher inputs the food, and the computer calculates the portion size, calories and nutrients.