You are hitting on exactly where “body positivity” needs to go… fat acceptance. Demolish the idea of the “good fatty”. We should not have to be killing ourselves trying to look different, lose weight in order to be a healthy person. And if thin people are allowed to not give a crap about pursuing health, ALL people should have the right to reject health pursuits — and I’m a health expert! I want people to want to work on health. But I really have little tolerance for focusing on appearance as a proxy for health.