Didn't need a study to know this
[1] httpss://www.medicaldaily.com/health-every-size-obesity-weight-loss-science-383008
Even without that, though, I'm sympathetic to HAES because it seems quite likely that, even if absolutely nothing else, focusing on body weight rather than lifestyle factors ultimately does more to discourage than encourage making healthier choices.
I personally know too many people who believe this shit. You can't say anything about it though or you're called scum and toxic. That too is healthy to them.