My 11-year old cat is starting to vomit frequently after eating. Should I change to a different food?

[lisahe]

When you're trying different foods, you might want to not only try different brands but different manufacturers. The manufacturers make many different brands. We found with our cat that there were particular manufacturers' products that did not work for her no matter which of their brands it was. It's not hard to check, just google "who makes brand name?" and they'll list it for you. Be ware that brands and lines are sold often and move from manufacturer to manufacturer.

Agreeing on all this. I'll also add (at least in our experience) often the reason for what K Kflowers bolded is that the manufacturer uses a specific ingredient in all/most of their foods and that ingredient just happens to be something a cat can't eat. Weruva, for example, uses potato starch and xanthan gum in lots of their foods, the "perfect portions" pates from Sheba and Nutro and Iams all have tapioca starch, and so on and so forth.

Beyond needing to watch who's making what where, it's very important to check ingredients regularly since recipes can change. It's also helpful to keep a journal of "incidents" and "last meal fed" since somethings the data you collect can help you see a pattern and determine that a specific ingredient (or even two) are likely culprits in causing symptoms.