Bowz,
While there could potentially be a problem, as the others have said, some children simply take longer to really get started on talking, and some of the kids that are late in that department end up speaking "normally" and even exceptionally. I knew a kid once who spoke, but he didn't speak a lot, I guess. However, suddenly, he took off and due to his mother using large words in front of him, he was getting quite the advanced words in his vocabulary, too. However, I would advise trying to speak more in front of him because a child will only learn to say and understand what they have heard. I know it must be hard to remember to do it sometimes, since you are naturally quiet, but it might help your kid's vocab develop a bit more fully, faster. Okay, I am responding as I'm reading and I noticed you say you do spend time each day going over words, and also read him books. These are great steps and the fact that he likes listening to the words is positive, I think.
As far as the not forcing him to eat thing, I don't think doing that would be a good idea, anyway. As I'm sure you know, eating too much is bad for your health, just like eating too little. And on top of this, eating too much sometimes make me feel nauseated. My guess is he will probably accept the food if he's hungry, as long as he doesn't think it tastes like absolute ick, and as long as everything is okay with his digestive system- if nothing about it hurts him or makes him sick, in other words. You seem to be handling it the right way. If your kid is eating enough that he's getting tired of it and spitting it out, I'd bet he's well fed. Maybe he's just not eating as much as you would have expected, but it's not necessarily abnormal.
About him playing mostly alone- this could simply be a difference in his temperment and personality. Also, this may change a bit overtime. The fact that he still comes to you for hugs and cuddles and enjoys the interaction time when you are speaking words slowly to him, sounds to me like he does still like interacting with you, and therefore, I wouldn't suspect an inability to connect with people. I am not a parent, but this is my take on things, for what it's worth.
By the way, you sound like a wonderful parent.