One study called out “the dirty secret of wearables,” citing that “these devices fail to drive long-term sustained engagement for a majority of users.” Endeavour Partners’ research found “more than half of U.S. consumers who have owned a modern activity tracker no longer use it. A third of U.S. consumers who have owned one stopped using the device within six months of receiving it.”

While the report mentioned several reasons why people don’t stick with these tracking devices, my own theory is simple, they backfire. Here are three surprising reasons why fitness apps may be making us less happy and more flabby.