You are kind of on the right track, half the plate veg, 1 third carb, 1 third protein, just theres not enough protein there
Shop bought meatballs arent really the best source of protein out there tbh. I know you are a working mum and time is tight, and probably money in this climate
If that was my grandchild, it would be similar, but instead of meatballs, bolognese made with Turkey mince, with a third of the weight of meat added red lentils - cheap filling protein and fibre and they melt in so picky kids ( and husbands) dont know - lots of onions, garlic, tomatoes and anything else I can throw in that I know he will eat. Slow cookers are a godsend, chuck it in, switch to on, come home and its done, just a pan of pasta to cook and a salad to rustle up. I personally use wholemeal pasta, for the fibre content, same as I only eat wholemeal bread, but a teen doesn't have those concerns, although learning habits for life isnt a bad thing :) When it comes to a salad - eat a rainbow. I prefer rocket, its expensive, I mix it with the cheap iceberg, I add tomatoes, cucumbers, onion, avocado , olives, pickles, roasted peppers - whatever Ive got in the cupboard and fridge . Even add halved grapes, blueberries , strawberries , a few seeds or chopped nuts
Like your son, grandson eats carp at school, its all they appear to serve ( Northern Ireland here so different rules ) plus hes on free school dinners which is a set amount and he swears its not enough to buy a decent meal. I dont know if hes totally truthful on that, hes a teen and loves the junk . However I do know that unless I give him a filling meal, lots of protein and veg, hes raiding the biscuit barrel when he should be sleeping
I just work with every meal has to be eaten at the table and every meal has to contain fruit or veg. Yes we have pizza, with salad instead of chips or garlic bread and yes he can eat a whole pizza himself, but he has to take the salad as well. Roast dinner, I pile on the spuds, along with the broccoli and carrots ( 2 veg he does like ), You dont get a bacon butty here, you get a BLT - lettuce and tomato - I shove the veg in where ever I can
Between the slow cooker and air fryer and planning ahead, supper is on the table within 30 mins of me walking in the door
As for the comments from parents, Id be having words.
I remember being a wee tub aged 12, I didnt get my curves until 14 , I too suffered in the changing rooms. Back in my day the role models were Twiggy and the ilk, there was no obesity so chubby kids got it tough and I still have body image problems now. I remember being "fat" sized 8 ( teen sized for some clothes ) and now age 60 I still struggle not to see myself as fat wearing size 10