Fitness trackers bad at keeping tabs on how much energy we burn

By Lisa Rapaport Reuters Health - Fitness trackers may be a trendy way to monitor every step we take, but these gadgets are actually pretty bad at keeping tabs on how much energy we burn, a new study suggests. Scientists pitted 12 devices like the Fitbit Flex and Jawbone Up24 against two proven methods of monitoring energy expenditure – locking people in a room to assess every calorie consumed and burned, or asking people at home to drink specially treated water that makes it possible to d