I lost 52kgs a few years ago for myself and my children.

I do not believe that you can be an overweight parent and it not impact your children negatively
I believe that is nonsense.
From an entirely statistical POV the father's weight appears to play a much greater role in childhood obesity than the mother's weight.
From an anecdotal POV I have friends who wear an XL (that's for extra lovely) with gorgeous, slender sporty children. On the flip side there is a Mum at my boy's swimming lessons who is gorgeous, toned and strong yet she has a fat kid.

No-one has mentioned the skinny-fat people yet. That is the people who have a terrible diet and don't exercise yet don't gain much weight. They have low muscle tone, crap cardio fitness and are as weak as kittens yet generally no-one sees fit to say that their unhealthy choices will impact negatively on their children. I guess it's because it's easier just to judge someone's parenting on their clothes size.

Fit is the new skinny