Just a note for the parent-shamers:
Both I and my stbx are a good weight and both do on average 3 sessions of fitness or sport every week. There are rarely ready meals in the house (and DD doesnt like those), not a lot of cake or biscuits, only occasional crisps and sugary drinks, takeaways are no more than once a week and pizza is always home made, and we buy only the most middle-class chocolate. The only member of family who is notably over weight she only sees a couple of times a year, and no one around her is a fitness evangelist. You couldn't model a much more balanced eating and exercise life.
Our daughter did various sports, week in week out for years (and yes, I stood in muddy fields freezing my **ts off cheering her on and supporting her) until she realised that, if she said No, we can't make her do it. She now refuses to get out of bed and go to school on time on the day she has PE first thing. She also used to cycle to school.
Then she changed school, covid happened and she became socially isolated. So she spends all her modest pocket money on books and junk food. Mostly junk food, because she's read half of two libraries.
She has very few friends and has fallen out with most of her friendship groups. This has undoubtedly been a contributary factor. So she comfort eats or bakes as a coping strategy.
When I try to talk to her about it, she turns all Kevin & Perry or blames me for fat-shaming, which is just her way of dismissing advice and taking the responsibility she wants to have.
So when you say you've never met an over weight kid who wasn't so because of their home environment, maybe you should meet my DD.
And yes, I know its my fault, and I beat myself up for it regularly. But I really don't know what else I could have done to be as perfect as some othe MNers.