I think anyone that supports bodily autonomy would support people being overweight. If you choose the body type you want and work to achieve it, you should of course have the right to do so. But I would guess (no source) that the vast majority of overweight people do not want to be overweight. No doubt they do not want to be overweight partially due to societal pressures to be thin, but also health reasons. Being significantly overweight is bad for your health, in almost every metric. Your life will be harder, and you will die earlier, but if someone chooses that, who am I to stop them??

And of course poor people( in western countries) are more likely to be overweight.