University analyzed the nutritional information and contents of 77 different dry cat food diets. 42 of these diets contained grain, while 35 were labeled as grain free. The major ingredients and amounts were determined for each diet and then analyses were conducted comparing the two groups. It was found that the grain free diets had a lower mean carbohydrate content than the diets containing grain; however, there was a very wide range and lots of overlap between the two groups in both their carbohydrate contents. Some grain free diets even had a higher amount of carbohydrates than the diets containing grain. Calorie amounts were similar for both diets. A recent study published by the FDA has potentially linked grain free diets to dilated cardiomyopathy in both dogs and cats. While the majority of cases reported were for canines, 14 cases were reported between 2014 and 2019 for cats. Allergy to grains is very rare in cats. Corn in particular is less likely to cause allergy than meat, fish, and dairy. There is also no evidence of gluten causing ill effects in cats. Vegetarian and vegan Vegetarian or vegan cat food has been available for many years, and is targeted primarily at vegan and vegetarian pet owners. While a small percentage of owners choose such a diet based on its perceived health benefits, the majority do so due to ethical concerns. Despite this, many vegans who feed their cats a vegan diet believe that a vegan diet is healthier than a conventional diet. There is much controversy over feeding cats a vegetarian or vegan diet. While there is anecdotal evidence that cats do well on vegetarian food, hard evidence is lacking on the adequacy (or lack thereof) of a vegetarian diet. As obligate carnivores, cats require nutrients (including arginine, taurine, arachidonic acid, vitamin A, vitamin B12 and niacin) found in meat sources. Plant sources do not contain enough of these. Vegetarian pet food companies try to correct these deficiencies by adding synthetically produced nutrients. Cats on a vegan diet can develop abnormally alkaline (high pH) urine as plant-based proteins are more alkaline than the meat-based foods which cats have evolved to eat. When the urine becomes too alkaline (pH > 5.4), there is an increased risk of formation of struvite (also known as magnesium ammonium phosphate) bladder crystals and/or stones. Calcium oxalate stones can also occur if the urine is too