For example Hypothyroidism, Cushing syndrome, pco-syndrome or lipedema and several metabolic deficiencies. Then there’s also a plethora of psychological issues that can influence the metabolism and eating habits negatively. Even the social status has an proven effect on the bodyweight.
All we have is a couple of pictures of the child, it’s impossible to tell what is going on.
Doesn’t matter if true or not, I choose to believe this now. Nobody ask for sources!