For most people, hasn't this "slow metabolism" myth been debunked?I have a super low metabolism and have to watch what I eat VERY carefully... but that doesn't mean I can't eat pizza once a week.
As long as you're active and eat healthy most of the time, you will likely not be obese. I'm still slightly overweight and working to fix that, but in general I'm healthy because I eat healthy and don't sit around all day.
With children, it's even easier than that.
Metabolism is, essentially, how much energy the body needs to function by burning calories.
On average, overweight people have slightly higher metabolisms than "normal-sized" people because overweight people need more energy to function.