Nancy is correct! Supermarket brands tend to be of low quality. My cats also had a problem of throwing up quite a bit, after eating. I did a comparison of ingrediants of what was in the brand that they were eating, and with Chicken Soup For The Cat Lover's Soul, and I was appalled. The brands purchased at the supermarket, were chock full of hard-to-digest grains, such as wheat, corn, and soy. On the other hand, premium brands such as Chicken soup, had easy-to-digest ingrediants, such as rice and oats, along with other wholesome protein sources. Aftermaking the switch to Chicken Soup dry food, I virtually never see any vomiting, unless it is hairball-related.
You will find the more premium brands at your local pet or feed stores. Some brands that I like, are California Natural, Innova Evo, Solid Gold, Felidae, and Pet Guard. There are scores of others, but the most important thing is to check the ingrediants.
Meow Mix may be tasty to cats, but it is full of artificial colorings and flavorings, to which cats can develope sensitivity to, over time. It also has low nutritional value, as compared to some of the brands that I mentioned above. Make a switch to a premium brand, and I bet you will see the vomiting cease.