A study based in Sweden surveyed owners of over 6700 cats and found that 1,369 cats had diabetes at the beginning of the study. The study looked at the weight, body type, and food types fed to the cats. The findings showed a link between feline diabetes and cats that stayed indoors, did not exercise, and ate excessively. Obese cats were more prone to diabetes, but interestingly, there was also an increased risk of diabetes among normal-weight cats consuming a dry food diet.
"This correlation, compared to normal-weight cats on a wet food diet, is a new and interesting finding that warrants further research, as a dry food diet is commonly fed to cats around the world." Ohlund and colleagues suggested that this increased diabetes risk could be explained because dry food puts an "increased demand" on the cat's insulin secretion.
I have been stating this for years, but I now have a scientific study to back my beliefs (yay). Dry food is chock-full of carbohydrates. Cats are not built to eat a high-carbohydrate diet. They are carnivores, which means they should eat meat, not corn and other grains and starches. Cats can process carbohydrates, but they break them down into simple sugars, which are an instant energy source for the body. Excess sugars are stored as fat, leading to obesity. The pancreas produces insulin to break down the sugar, but many cats eventually suffer from pancreatitis (inflammation of the pancreas), pancreatic exhaustion and depletion of insulin production, and insulin resistance. Eventually there is not enough insulin to process the sugar load and the cat becomes diabetic.
Diabetic cats must be regulated using insulin injections. Many pet owners are unwilling or unable to perform daily injections, resulting in the demise of many cats.
If you want your cat to live a long healthy life, STOP FEEDING DRY KIBBLE LOADED WITH CARBOHYDRATES. Feed a species-appropriate meat-based diet. Cats need a high moisture diet to maintain good kidney health and avoid urinary crystals, stones, and early kidney failure. Raw meat, gently cooked, or even canned meat feline diets are a much better choice for cats.