A.M.
My son was a great eater and then he had a little stomach virus for a few days that ruined everything. I was having the problem you described. I asked for advice on mamasource and the most common was to offer him something and if he didn't eat it, too bad. I hated putting him to bed knowing he hadn't eaten much but I figured one or 2 days wouldnt be so bad. I told myself that if after this, he still wouldnt eat, that I would just give in and cater to his pickyness. Well after the first day, he woke up so hungry that he ate his entire plate of omelete and cottage cheese. I was having a hard time getting him to eat egg so I was very happy. Then I skipped his usual snack and waited until lunch in which I offered him a large portion of sliced cheese,carrots,and chicken nuggets. He ate EVERYTHING. I was so happy. Then at dinner, he almost finished his whole plate of meatloaf and corn. The next day I made his aportions a little smaller and went back to giving him yogurt and fruit for snacks and now he is back to being a good eater.
The Moms told me that my son would not starve himself and that if he knew I would give in and give him what he wanted, that he'd turn down what I originally offered him. But if you do not offer him anything after he turns down the food you give him, he will eventually figure out that if he doesn't eat, he won't get anything else. Also, if your son is the type to snack all day, its easy for him to turn down food if he's not really hungry. Try waiting longer periods in between meals and seeing if that helps.
Also, I find that my son will pretty much eat anything if I serve it with a small side of ketchup. And if I cut it longwise rather than in bits, he loves it. When I feed him meatloaf, I cut it into strips before giving it to him. He prefers to feed himself. Banana and melon, I cut in long slices too. Same with cheese,hot dog weiners,nuggets,meat,chicken,potatoes...pretty much anything that needs cutting. Mashed potato,yogurt,cottage cheese,corn,etc I put in a tiny little plastic bowl and he will spoon it into his mouth himself. He makes a mess so I always take his shirt off before a meal but at least most of it gets in his mouth. :)