I expect that plenty of these apps are or will be mining these photos for data about their users. I know the cat is already out of the bag as far as online tracking goes, but until now, tracking every meal & snack someone eats has been impossible (except perhaps for the most consummate doordash user).

And the companies most interested in the data would be the large food corporations who bear a lot of responsibility for getting us into this obesity crisis in the first place.