Yes food can cause a UTI, my cat is living proof. She was 7 yrs old when she had her first one & that's because a year earlier my vet prescribed a fat cat diet. She was on RC Calorie Control. After she got the UTI, I really looked at the food. I contacted the company & it has high phosphorus & almost 25% DM carbs. It's crappy in other words. I changed her food & she hasn't had any issues, until tonight of course.....Stress can cause uti. I have never heard of food causing it. Also litter box not regularly scooped and not getting enough water so canned food for the extra moisture and help the teeth. Males are more to uti and blockage/crystals. Another sign is cleaning his genitals a lot My cat had uti,went back for a recheck and she had struitive crystals. Glad you are keeping an eye on him.