He is 12, 5'2" tall and has outgrown his 12yr old school trousers. I couldn't get him any 12/13 yr old ones so had to get 14/15. I took the waist in so they fit but are too long on the legs. He is quite flabby TBH I know long term he will grow out of it as both my DB and I went through a sort of pupa-stage in their early teens when they were fat, only to emerge tall and skinny in our late teens. But I am worried that he basically eats too much and for the first time in his life is quite sedentary.
He is becoming self-conscious of his weight and hates PE (for this reason I think). But atm he is very reluctant to change his eating habits. He tries to ride his bike with me when I go running but he doesn't want to most of the time. He walks to school and skates but that is about it these days.
How can I convince him without making him even more self-conscious? I'm cutting back on his portions, stopping him snacking - he used to snack on fruit which is Ok but it was by the KG . And drink fruit juice in litres.
As he is quite old I want to get him on board. What are your best tips for encouraging a reluctant and hungry 12 yr old (without resorting to calling him fatty that is)?