As someone who has yo-yo'd from 190 to 315 a few times in my life until I figured out what worked best for my body, it never ceases to amaze me how much raw anger I receive anytime I try to, even in passing via social media to suggest that maybe it's their diet. I was a gym rat for years, but with age, it became clear diet is king.
Furthermore, the pure vitriol I have sometimes received is hard even to describe; it's a kind of instinctual rage to prevent hearing what might be the truth. Some went so far as to claim self-harm or attack me in real life for having the gull even to mouth my beliefs in their general direction.
Lastly, to your article, once thin, I am given routine speeches by people who have no idea who I am and how long I've struggled with my own weight loss, lecture me endlessly about my thin privilege even sometimes in real life. Most grow very quiet once I show them photos, but even then some still insist that the fact that I could lose the weight makes me unelledigble to help them. For my own sanity, I just let people come to me now if they want help and shoot people down hard if they ever lecture me.