Diabetes mellitus, also known simply as diabetes, is a disease that is characterized by chronically high blood sugar levels. It leads to increased thirst, pathological weight loss, poor quality hair, weakness and neurological problems. If it is not treated, diabetes ultimately kills affected cats.
Feline diabetes is similar to type 2 (adult onset) diabetes in humans. Obesity is a known risk factor for the disease.
Many people, including many veterinarians, have speculated that commercial cat foods, especially dry foods, also contribute to the development of diabetes in cats.
In the wild, cats eat a diet that is high in protein and low in carbohydrates. Commercial foods, especially dry foods, have high levels of carbohydrates. Carbohydrates are readily converted to sugar in the body. Therefore, chronically high levels of carbohydrates in feline diets may contribute to the development of diabetes.
In theory, this makes sense. However, theories like this are easy to test. Take two groups of cats: one that eats dry food, another that eats wet food. Control for confounding variables such as obesity, age and breed. Compare rates of diabetes.
The April, 2008 NAVC Clinician’s Brief contains a summary of just such a study. From the summary:
Analysis of data . . . showed no significant correlation between dry food consumption and development of [diabetes mellitus]. Since dry cat food has a much greater carbohydrate content than canned, high carbohydrate intake also did not appear to be a risk factor.
In my opinion the conclusion that carbohydrate consumption is not linked to diabetes may be a bit of a stretch (I feel that the study was not comprehensive enough to draw such a broad conclusion). However, the study does provide solid evidence that dry food is not specifically linked to increased risk of diabetes.