Over the years I have done some reading on this topic (because I once had a cat that did this all the time). What I have learned is that this is a "normal thing" for cats. It seems that when they are in the wild they generally don't have the time to chew and swallow their food. So they have adapted by gulping down their food which is later digested in the stomach. The best thing to do is to feed smaller portions at a time. If he vomit you might want to wait a little while before putting more food out for him.

The cat I mentioned above (Meow) used to eat the food extremely fast and then get sick at my feet. Meow was also over weight and after a few months of not feeding him again right after he got sick, not only did he loose some weight, but he was also more careful about vomiting.