At our kindy families are asked to do a photo collage at the start of the year (pics of family, best friends, pets etc) and the children can look at them and talk to the staff about them etc it can help some of the kids missing mum/dad / having a bad day etc.
Not entirely sure what to suggest - my DS1 went through the separation anxiety thing around 18 months he cried every time I dropped him at daycare but only 5 minutes he was always happy there it was just drop off. That settled in time. We never had the refusing to eat thing, TT was a bit hit & miss at daycare he wouldn't do number 2s in their toilets for ages and had several accidents because of it. A few months later he was fine, the staff really helped by praising him when he made the effort etc, and he is the kind of kid that responds well to praise.
If you haven't already ask to have a meeting with his room leader and any other applicable staff and discuss your concerns. I find more often than not, the staff at our ELC are very supportive and offer help when needed. If they are aware of your concerns they can make some suggestions as to how they can help on their side.
If his anxiety is a real issue and you think he needs more help (if it gets worse/continues etc) maybe seeing a child psychologist or similar might be worthwhile? They may be able to give you some practical ideas to help with his anxiety. Our centre often advertises workshops etc to help with this kind of thing and they are run by a children's behavioural psychologist.