I am another who thinks it could go either way. Social eating is positive, school means are generally pretty uninteresting and not necessarily healthy (IMHO - and I am NOT a fussy eater!)
Can you do a combination thing? Packed lunch two days and school meal the others? That is what my dd does.
Our school does roast dinners on one day and fish or something and chips another (the same day each week as a regular) and so we can pick the type of meal our children may like.
I had a school meal with my son the other day. ('Taster' day!) It was not that great but was OK. The meat was a bit rough but roast spuds nice. Only one vegetable offered, we have at least two at home if not more. There was a pudding, which my son liked; but as an overweight person myself I am not sure that any kid needs encouragement to eat sugar.
I am not sure I would think of a roast dinner and a pudding as healthy eating but I am happy for my son to like it and eat it as he is fit and runs about a lot and I am sure it is not unhealthy either, if that makes sense! He is fussy but he does get enough nutrients and seems very healthy.
And totally agree with krustyem kids have their own minds, they are individuals.
And actually eating everything that is put in front of you is a very bad thing in our food-laden culture. Learning to discern what you like, what is good for you, what you need at that time, to know when you are full, etc etc are all very useful things. As long as a child is getting enough nutrients to thrive I think it is fine.
I would give it a try but, just my personal opinion, making food fun might help. I would also work on the food thing at home as I am sure you are. Maybe make it as much fun/the child involved as possible. Make fruity faces, make your own salad 'recepies', let your child help to choose, plan, shop for and prepare bits of meals that are safe for them to do. Breaking up broccoli with fingers, mixing sauces, mashing potatoes etc. You can get child friendly serrated teeth knives, but I am quite-knife nerouvs with kids so don't do anything you are not happy with!
I am talking specific kid knives here!
ecosweetie.com/product/ecoshark-kids-biodegradable-pla-safety-knife/
My dd (10) has been very fussy and has got less so but was a brilliant eater as a baby. It comes around and goes around IMHO. But the worst thing is for food to be an issue or a power thing so I never make my kids finish up their food or eat anything except a bit of vegetables. By that I mean they must eat some veggies but not all and never make them clear their plate of veggies. I now encourage them to eat a few of their veggies first as these cool down quicker than meat or pasta etc (usually) and I often offer finger food sized bits of tomato and cucumber with salad cream to dip at every meal. So some veg is cold and easy to eat. Eating veg first when they are most hungry and the hot veg food is still warm is much nicer than waiting for them to eat them at the end.
I always said I would never make my kids eat up food but I have changed a little on the veg as my son is so veg averse!
Hope that makes sense.