It is well established that equating calories burned from exercise with those taken in doesn’t work .. basically we can’t measure the input numbers well enough and calculate a personal metabolism accurately enough to make a meaninful call. In fact evidence suggests fitness trackers are a bit worse than no tracker if weight loss is the goal (over time means > one year).
A new study has a twist .. lifestyle intervention plus a fitness tracker . The wearable was only doing the exercise component. What is interesting is the people who used the fitness trackers did significantly worse than those who didn’t use one.
The caution is human metabolism and the measurement of interventions is very very tricky and it is easy for biases to creep in. Perhaps devices will get smart enough to do expert coaching, but our understanding of our social and psychological nature is probably more primitive than that of metabolism.
I still like the idea of devices for people who want one .. weight management is *much* less important than physical conditioning. It has been shown that motivated people tend to increase their level of conditioning independent of device .. but if one fits your personality, then it probably should be considered a necessary device. I’ve seen successful exercises swear by and at fitness trackers and I’ve seen the same from people who have failed.