Eating Problem

Michael will not eat his dinner or lunch. Sometimes he will do a good job but overall it is a few bites. There will be days he will not eat lunch and only a few bites of dinner. I have done the you can't leave the table until you have eaten and also the fine if you don't eat you won't get anything else later when you are hungry. Nothing seems to work. I know he is hungry because when he wakes up in the morning he wants breakfast right away because he is starving and he will eat breakfast. I feed him things that he likes and he is not a picky eater. I'm not big on the bribe thing because he thinks dinner is always followed by desert. The times I have tried it, it does not always work. I was wondering if anyone else has this problem and what were your solutions to solving this problem.