My son (currently 23 months old) attends an in-home daycare 5 days a week. The daycare provider cooks homemade meals for the kids, and provides snacks.
By every report she gives, our son gives her absolutely no trouble when it comes to eating whatever she presents him.
However, my wife and I are unable to get him to even taste most of the food we prepare, or even food we get at restaurants.
He has a small selection (of rather eclectic diversity) of foods that he will gladly eat, and a few other foods that he will generally be willing to taste (e.g. anything that looks like ground beef, or is wrapped in a tortilla, he'll generally take at least a bite out of).
However, the vast majority of foods, when offered to him, will result in him saying "no!" and turning his head away. Usually there is a small smile on his lips when he does this. With some persistence, we can sometimes get a small amount of it past his lips, but usually only because repeated attempts seems to turn it into a game for him, and I can sneak in a tiny mouthful while he's laughing.
Typically, we'll offer him a small amount of whatever we're eating. When he refuses to try it, we'll then give him something else that we know he likes (chicken nuggets, hot dogs, baked beans, unsweetened apple sauce, just about any kind of soup, grilled cheese, homemade pizzas, etc.). However, we'd really like him to at least try whatever we're eating.
We've tried not offering anything else, and he simply will ignore the food and want to go and play (my wife is not comfortable letting him go without any food, so eventually he will get a snack, or some milk, some time after dinner is over).
We've tried enforcing "you can't leave until you at least try a bite". That results in massive melt-downs that are wholly atypical for him. Our longest foray down that road lasted over 45 minutes, ending with him sobbing uncontrollably after coming out of a short time-out.
I feel that he may simply be too young for "you can't leave until you at least try a bite". At the same time, it seems pretty clear that not trying food has become a game he plays with us. He doesn't have any problem at daycare, but that may also be because he sees the other, older kids eating, and wants to emulate them.
What is the best way to get him to try new foods?
Edit to clarify:
The issue is not that he is refusing to eat meals, and is instead eating only snacks. He is refusing to try some meals, but eats others.
He's not refusing to eat dinner, and instead eating a dish of ice cream. He's refusing to taste pork chop, but will eat a bowl of vegetable soup; he's turning up his nose at a hamburger to eat a taco (with veggies); or he's pushing away fish sticks to enjoy a homemade whole-wheat pizza with bbq chicken, onions, and green peppers.