DS is 11 has ADHD and some sensory issues. A few foods are definitely sensory triggers (mushrooms, any food if it's not cooled down yet) but the rest of the things he'll eat have decreased over the last year and become more inflexible (e.g. only two kinds of white bread, where he used to eat almost any bread).
He eats a good amount (putting on weight despite meds) and several fruits and veggies so I'm not worried he's going to starve.
He used to eat most things at school (at his old school - he moved in June from a PRU to a specialist SEMH school. Now he might eat a baked potato with tuna or a tuna sandwich some days. Lots of it is behaviour - I know that's not fashionable to say but he let on he was throwing his lunch on the floor to get beans on toast when he got home at 3.
We offer a snack later after tea (usually an hour later) but he just rejects tea and has a bowl of cereal instead later. Lots of the meals we have he'll eat but only 1 time in 3 and they are getting more hit and miss. So we have broccoli mac and cheese and he'll refuse it, shout and run off, then eat it later one time, eat happily the second, and then refuse entirely the third.