Food will not be an issue at CUSAT. The food you will get at the mess of CUSAT is similar to that of any other engineering colleges in India.
The food provided at the campus is great. But it is Kerala food. If you are from North India and habituated to the type of Noth-Indian food, you may have difficulty in adjusting. Since the food at the mess is prepared in coconut oil. If you are opting for a hostel you have to choose the mess facilities too. But it is not as bad as it sounds, and you can survive and adjust with time.
You can get Noth-Indian Food by tiffin service too. You can also find many Bihari and Bengali cooks in the vicinity of the campus. There are also a few North-Indian messes near the college. In case you are staying in a rented flat or room, it would be better to hire a cook.
It may take some time to adjust but you can definitely survive on the food available at CUSA. So, do not treat food as a deciding parameter for not choosing CUSAT.