@ Quintin's mom,
I'm glad to hear that things have improved considerably with Quintin. He's lucky to have a parent who is willing to take cues from him instead of turning meal times into a battlefield.
I was Quintin when I was younger. Back then, nobody was talking about Asperger's & I suspect only a handful of specialists really knew much about it. Kids like me got branded as odd, difficult, spoiled, weird & other less flattering labels. One thing my mother did right was to supplement my sparse dietary options with a multivitamin & an iron supplement.
As a kid, I took a pb & honey sandwich on crustless bread (cut into 4 squares) for lunch every single day for a good 4 years straight. With that, there had to be a med sized RED apple & a small bottle of oj. That's it that's all! For supper I'd eat macaroni & meat sauce. As far as vegetables went, I'd eat peas (small ones only!) carrots (steamed & cubed) & corn (NOT on a cob). Sometimes spaghetti could be substituted for the macaroni or rarely mac & cheese. I'd eat some hamburgers or a hot dog (had to be made to strict specifications). I did like several fruits.
Now, as an adult, I've broadened my dietary spectrum. Still, foods cannot touch or be mixed on a plate. I won't risk eating mashed potatoes anyone else made for fear of encountering a disgusting lump. I'll eat most fruits but NEVER mixed together in a salad. I don't eat any sauces other than my meat sauce or my cheese sauce. Meat has to be free of any tiny fat lumps & must be cooked right through: no pink parts. I don't tolerate lactose & I get ill from any sea food. In order to remain healthy, I take a variety of supplements & according to my Dr. I'm not nutrition deficient in any area. Your son can still be healthy while remaining true to his finicky self. Pushing & forcing could trigger a power struggle that you're guaranteed to lose (& so will he as his stress level sky rockets & his health decreases).