Is it safe to only feed a cat dry food?

Should cats have a more complete diet or not? My cat rarely eats anything else apart from dry food, and I do not know why


The short answer is "yes".

The longer answer is yes, a cat can be fine on a diet of only dry food. Most of the dry food brands are formulated to contain all the nutrients a cat needs.

The main thing to be careful of is that cats tend not to drink enough (since in the wild they get most of the liquid they need from their prey) so you do need to make sure the cat always has access to fresh water and learn the signs of dehydration.

Your cat could simply prefer the dry food. Cats have definite preferences - with our three we have one fussy eater who turns up her nose at the wrong kind of wet food, one who'll eat anything that resembles food, and one somewhere in between.

  • 2
    You beat me to that answer! Indeed, the big issue with dry food is moisture content for cats that don't like to drink. – John Cavan Jun 3 '14 at 12:51
  • A big plus for dry food is that it is better for their dental health. – Beth Whitezel Jun 5 '14 at 6:44
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    @BethWhitezel that's a common belief that research has been unable to confirm. There are a small number of foods that can help, but not as a broad category. – Zaralynda Jun 5 '14 at 12:48
  • I like to offer flowing water via fountain for cats for just this reason. – Preston Jun 8 '14 at 22:22
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    @PrestonFitzgerald I do the same. We used to put water out in a dish, but observed that our cat didn't drink much water that way because it would get dirty very quickly. We got him a Drinkwell, and he definitely is more willing to drink running water. We haven't measured anything, but he seems much healthier to us. – Ben Collins Feb 9 '15 at 21:13

Cats can survive on a dry food only diet, but there are health concerns so that I wouldn't consider it to be safe.

Water Content

The first concern is water content. Cats evolved to get water from their prey, they only drink a small amount. When cats are fed dry food, they do not drink enough water to make up for the deficiency and become chronically dehydrated.

WALTHAM® Centre for Pet Nutrition (the science centre supporting Mars Petcare brands such as WHISKAS® and ROYAL CANIN) performed a study that showed:

When cats were fed the 73.3% moisture diet they produced larger volumes of more dilute urine with a lower risk of stone formation than when they were fed the lower moisture diets

When cats do not consume enough water, they can be subject to the following health risks:

  • Interstitial Cystitis (inflammation of the bladder walls)
  • Urethral Obstruction (blockage so the cat is unable to pee, this is an EMERGENCY as it can progress to bladder rupture if not treated)
  • Urinary Tract Infection
  • Chronic Renal Failure

All of these conditions are extremely painful, and can cause litter box aversion since your cat only understands that it hurts when they are in the litter box. Even once the medical condition is fixed, a cat who has developed litter box aversion may not return to the litter box without significant training.

Carbohydrate Content

The second major concern is that dry foods have a high level of carbohydrates, which is inappropriate for a cat's digestive system.

Cats have a physiological decrease in the ability to utilize carbohydrates due to the lack of specific enzymatic pathways that are present in other mammals, and they lack a salivary enzyme called amylase.

When cats consume too much carbohydrates, they can be subject to the following health risks:

  • Diabetes
  • Obesity
  • Allergies (many cats develop allergies to substances they cannot digest)

Other Concerns

Dry food is coated in animal digest to make it smell appetizing for cats (this is why many cats prefer dry food over wet food), but it can cause them to overeat.

Dry food has been found to have mold, fungus, mycotoxins, storage mites from improper grain storage.

  • Evalutation of storage mites in commercial dry dog food. Vet Dermatol. 2008 Aug;19(4):209-14. doi: 10.1111/j.1365-3164.2008.00676.x (link)
  • Estimated 100 dogs die from aflatoxin poisioning. It takes 2-3 months to link the deaths to the food source and issue the recall. (link)
  • Another recall of food with high levels of aflatoxin (link)
  • 2
    I agree with Zaralynda. Basically dry food is low quality food, you are probably shaving months or years off your cats life by feeding them only that because you are setting them up for other problems (kidney disease and other fatal UTI conditions, diabetes,...) – Dan S Jun 8 '14 at 19:58
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    Deceptively untrue @DanS. There are plenty of high-quality dry foods just as there are plenty of low-quality wet foods. – Preston Jun 8 '14 at 22:24
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    @PrestonFitzgerald the worst quality wet food is better than the best quality dry food because of the water differential. Yes cats can live on dry food, but people can also live on McDonalds. In both cases, the food will often make the person/cat ill over time. – Zaralynda Jun 9 '14 at 2:17

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