Wet or Dry Food: Which Is Better for Dogs?

Wet or dry dog food can both be a good choice. What matters most is that the food is labeled complete and balanced for your dog's life stage, which the FDA says means it is meant to be fed as the sole diet.

The Merck Veterinary Manual lists lower cost and easy storage as dry food's advantages, and long shelf life and high palatability as canned food's. The biggest difference between them is water.

What is the real difference between wet and dry dog food?

Mostly, how much of the food is water. Merck puts dry food at about 10% water and canned food at 68% to 78% water. The FDA gives canned food as typically 75% to 78% moisture and dry food as 10% to 12%.

In other words, a can of wet food is around three-quarters water. That one fact explains most of the other differences, from price per meal to how much your dog drinks.

Merck notes that dry food is the most popular category of pet food in the US. Canned foods typically contain more fresh or frozen meat, poultry or fish, and the sealed cans are heat- and pressure-cooked, which sterilizes the contents.

There is a middle option too. Merck describes semimoist foods as 25% to 40% water, kept shelf-stable with ingredients that bind water so bacteria and mold can't use it.

Is wet or dry food healthier for dogs?

Neither form is healthier by default. The FDA explains that a food earns a "complete and balanced" claim by meeting an AAFCO nutrient profile, which means containing every listed nutrient at the recommended level, or by passing an AAFCO feeding trial.

Both wet and dry foods can carry that claim. WSAVA's guidelines add that the label should say which life stage the food suits, and that a food labeled "for all life stages" is formulated for growth and reproduction.

Comparing labels: the dry matter trick

Here is the part most people miss. A wet food label looks lower in protein than a dry one, because the percentages include all that water.

The FDA shows how to compare them fairly. Subtract the moisture percentage from 100 to get the dry matter, divide the nutrient by that number, then multiply by 100.

In the FDA's own worked example, a canned food listing 12% protein at 78% moisture works out to 54.5% protein on a dry matter basis. A dry food listing 37% protein at 12% moisture works out to 42%.

So the food that looked lower on the label had more protein once the water was taken out. The FDA's example uses cat foods, but the arithmetic works the same for any two foods.

Does wet food help a dog drink enough?

It adds water, and dogs adjust. Merck calls water the most important nutrient, and notes that dogs and cats eating mostly canned food generally drink less water than those on mostly dry food.

How much water is enough? Merck puts the need for most mammals, in a comfortable temperature, at roughly 44 to 66 mL per kg of body weight a day.

By our arithmetic, that is about 440 to 660 mL, or two to three cups, for a 22 lb dog. Water in the food counts toward it too.

Whatever you feed, keep fresh water out all day. Merck advises that when plenty of water is available, intake should not be restricted.

Our guide on how to keep a dog hydrated has more on helping a dog drink enough.

What about cost, storage and food safety?

Merck lists lower cost as an advantage of dry food, along with being able to store unused portions at room temperature. Canned food keeps a long time in its sealed can, but Merck notes it costs more than dry.

The FDA's safe handling advice explains why storage matters: pet food can be contaminated with harmful bacteria that cause foodborne illnesses, in pets and in the people who handle it.

• Promptly refrigerate or throw out leftover canned and pouched food, with the fridge at 40°F or below.
• Store dry food in its original bag with the top folded down tightly, somewhere below 80°F.
• Wash bowls and scoops with soap and hot water after each use.
• Wash your hands for at least 20 seconds with soap and hot water after handling pet food.

Does wet food mean fewer calories?

Per gram, yes, but your dog may simply eat more. Merck explains that only protein, fat and carbohydrate supply energy. Water does not, so a high-moisture food carries less energy in each bite.

A 2017 study in the Journal of Nutritional Science tested whether that helps. Researchers offered 46 miniature schnauzers twice their daily energy needs as either plain kibble or the same kibble with water added to 72% moisture.

The dogs on watered kibble gained weight faster, by about 19 g a day. The authors concluded that adding water was "not a useful strategy for maintaining body weight" when food is plentiful. The authors work for a pet food company.

The practical answer is to feed by calories, whichever form you choose. WSAVA notes that US pet food labels are required to list calories, and that knowing them can help prevent unintended overfeeding.

Merck adds that any individual dog may need as much as 30% more or fewer calories than a formula predicts, so the label's feeding guide is a starting point. Your vet can help you adjust it.

Can I mix wet and dry food, or add a topper?

We found no veterinary source comparing a mixed bowl with either food alone. If you combine two complete foods, check the calories on both labels so the total stays where your dog needs it.

Toppers follow a simpler rule. WSAVA's guidelines say products labeled for "intermittent" or "complementary" feeding should make up 10% or less of the diet. Our guide to dog food toppers covers how much to add.

One option for a topper is Total Balance, a lickable daily stick you can squeeze over your dog's usual food. It is made with tuna, cod, salmon and lobster, and provides vitamins A, B2, B3 and E, iron and zinc.

It is labeled for intermittent or supplemental feeding only, lists 12.4 kcal per stick, and is meant for dogs and cats from 12 months old. It goes alongside a complete food, never in place of one.

If you're weighing up the same choice for a cat, our guide to wet or dry cat food covers the feline side.

When should I talk to my vet about my dog's food?

Before you make a change. Your vet can help match the food, the portion and any toppers to your dog's age, size and activity.

Call your vet promptly if your dog has:

• not eaten or drunk anything for 24 hours
• started drinking far more water than usual
• sudden weight gain or loss
• extreme tiredness, or is sleeping more than usual and doesn't want to play

Merck's veterinary manual lists each of these among the signs that mean a dog should see a vet.

Questions new dog parents ask

Is wet food better for dogs than dry?

Not automatically. A complete and balanced food in either form can be a dog's sole diet, according to the FDA. Wet food adds water and is highly palatable; dry food costs less and stores more easily.

Is it OK to feed a dog only dry food?

Yes, if it is complete and balanced for your dog's life stage and fresh water is always available. Merck notes that dogs on mostly canned food generally drink less, so expect a dry-fed dog to visit the water bowl more.

How much wet food equals a cup of dry food?

There is no single conversion, because foods vary. Compare the calories listed on each label, which US labels are required to show, and ask your vet to check the portion.

Can puppies eat wet food?

Yes, if the label says it is complete and balanced for growth or for all life stages. WSAVA notes that all-life-stage foods are formulated for growth and reproduction.

Sources

• Merck Veterinary Manual: Dog and Cat Foods
• Merck Veterinary Manual: Nutritional Requirements of Small Animals
• Merck Veterinary Manual: When to See a Veterinarian
• FDA Center for Veterinary Medicine: “Complete and Balanced” Pet Food
• FDA Center for Veterinary Medicine: Tips for Safe Handling of Pet Food and Treats
• WSAVA Global Nutrition Committee: Guidelines on Selecting Pet Foods, 2021
• Alexander JE, Colyer A, Morris PJ. The effect of reducing energy density, via the addition of water to dry diet, on body weight and activity in dogs. Journal of Nutritional Science, 2017

This article is for general information and is not veterinary advice. Talk to your vet about your own dog — they know the animal in front of them.