A parent I saw yesterday wheeling a 2 or 3 year old in a buggy. The child was seriously obese. Parent gave said child a can of Pringles to eat on while she shopped as she was whinging.
I think this is grossly unfair on a child as young as this, setting her up for a myriad of health problems. The child is more likely to develop diabetes and probably less likely to take up sports etc as they get older (which is hugely important for personal development imo).
I am aware there are other conditions that can cause children to put on weight, medication, learning difficulties etc (and these are not the scenarios I'm talking about) but other than that, it's the parents responsibility to manage the toddlers weight and activity levels. It's very sad tbh.