Because of the popularity of grain free diets for people, this method of eating is slowly creeping into animals foods. Is it healthy for cats to eat a grain free diet? The answer is a cautious yes as long as another carbohydrate such as potato is not substituted for the grain. Let me explain:
Many studies (and common sense) have demonstrated that cats are strict carnivores meaning they need to consume animal tissue in order to satisfy their unique nutritional requirements. Mice, a common prey for cats, are primarily protein and fat with very few carbohydrates. Dry diets fed to domesticated cats are loaded with carbohydrates. Whether the carbohydrates come from grains or other sources, cats cannot metabolize them into sugar like dogs and humans. Therefore, carbohydrates from any source should be minimized in cats. Since all dry food is loaded with carbohydrates, the current recommendation is to feed cats canned food without gravy. Remember gravy contains a lot of carbohydrates.
The bottom line is that cats should eat a very low carbohydrate diet to prevent diabetes, pancreatitis and a host of other problems. When I evaluate a food that is marketed as grain free, I look very closely to see what other carbohydrate source has been used. Most of the grain free diets I have evaluated substitute potatoes and rice for the grains. Unfortunately, the glycemic index is even higher for these two starches. Read all cat food labels carefully and consult with your veterinarian to determine what is the best food for your cat.
-Bradshaw, John W.S. “The evolutionary basis for feeding behavior of domestic dogs (Canis familiaris) and cats (Felis catus). J. Nutr. July 2006; 136(7Suppl): 1927S-1931S.
-Hewson-Hughes, A.K. “Geometric analysis of macronutrient selection in adult cat, Felis catus.”
J. Exp. Biol. March 2011; 214 (Pt6): 1039-51.
-Plantinga, E.A., et al. “Estimation of the dietary nutrient profile of free-roaming cats: possible implications for nutrition of domestic cats.” Br. J. Nutri. October 2011; 106 Suppl. 1(0): S35-48.
-Verbrugghe, A. et al. “Nutritional modulation of insulin resistance in the true carnivorous cat: a review. Crit. Rev. Food Sci. Nutr. January 2012; 52(2): 172-82.