My son is 13 and every day recently, I've put his breakfast on the table for him before school, and he'll either nibble a bit of leave it completely

I’d talk to him honestly, he’s 13 already. I’d ask his honest input about the breakfast, ask how are his feeding habits happening at the moment. Maybe he’s got a social thing going on at school and doesn’t want to eat how and when he used to. I’d do the maths on speeadsheet/chat gpt and show him how much he’s wasting in $ per year, and explore where could this money be invested in *for the family*, not for him as he’ll probably feel entitled to that money (make teenager thing, nothing personal against your son - I don’t know him)

I remember that age I didn’t eat breakfast or eat during school . For me I think it was an anxiety thing as I didn’t like school and I was always rushing in the morning so much that I wasn’t hungry and at school I’d just eat a small snack And come home starving . I was also packed tuna sandwich etc and kids would say my food smelled so I’d just keep that lunch box shut 😭 I also prefer warm meals so sandwiches etc I didn’t care for . I’d say pack snacks that are easy to eat on the go and focus on healthy dinners and snacks at home . Hopefully it’s just a phase 🤍

Remove the pressure so it doesn't become a bigger deal. He may not have the appetite before school, so pack it with him. Or make it a smaller breakfast. A fruit, drinkable yogurt, small pastry. I would pack his lunch as usual and tell him he needs to eat that before he eats anything at home, even if he isn't eating it in school.

Do they serve breakfast and lunch in school? Maybe it's time to stop making his meals altogether