Fun story: a friend of mine ballooned up in a few months after joining a "gender studies" group. So, he decided to "prove me a fatphobe" by showing that a fatty can run 5K in 35 minutes (which any person could do in a month of training). After 3 months of "training", he did manage to beat the time (in a treadmill, but ok). However, by then, he lost 10kg/22lbs and was no longer overweight. Shortly after, he was asked not to return to the study group because his presence was "harmful" to their "safe space". He got really sad, but accepted and ended up apologizing and leaving.