Your dog looks at you with those big brown eyes. Your heart melts and you reach for a treat. But a dog biscuit isn’t necessarily the best way to show your pup love. A healthier alternative would be to give him a gentle scratch behind his ear — or better yet, take him for a nice long walk.

“Most of us confuse affection with confection,” says Ernie Ward, DVM, founder of the Association of Pet Obesity Prevention (APOP). Ward says this is likely one reason more than half of dogs in the United States are overweight or obese.

It doesn’t help that dog owners often can’t tell that Fido is fat. If you can’t see your dog’s spine or feel his ribs by gently rubbing his chest, he’s overweight. You also should be able to see his waist, which is an indentation between his ribs and hips.

A serious problem that’s preventable

“Being overweight isn’t healthy for humans,” says Ward. “It’s no different for pets. Carrying around extra fat increases the risk of heart disease, arthritis, high blood pressure and Type 2 diabetes. It can shorten a dog’s life.”

Related: 13 Health Symptoms Dog Owners Should Never Ignore

When Ward treats an overweight dog, he first checks for problems like Cushing’s disease, an endocrine disorder that causes fat around the belly. If an illness is ruled out, then Ward will put the pooch on a diet and prescribe more exercise.

“This really is a process of retraining people and their pets,” he explains. “I’ve never seen a dog that would prefer food over play or attention. Instead of filling your dog’s dish, go for a walk, pet him or give him a good brushing.”

A proper doggy diet

The best way to deal with extra pounds on a pooch is to prevent them from sneaking on in the first place. This means feeding your dog properly starting when he’s puppy. If he still winds up overweight (or you adopt a dog that’s already a chubbo), you can adjust his diet and activity to help him get his slender figure back.

What food should your dog eat? Dogs are omnivores. Even though they can subsist on a vegetarian diet, most veterinarians recommend giving dogs protein in the form of meat, poultry or fish. Look for a dog food that lists one of these as the first ingredient, followed by vegetables, and that says it’s free of chemicals and meat-by-products. These foods won’t necessarily help your dog lose or maintain weight but they are healthier options and will contribute to his overall well-being. The best part: You often can find such foods in your local supermarket.

Related: The Downsides of Homemade Dog Food

How much? It depends on his size, breed — obviously a Great Dane will eat much more than a Chihuahua — and life stage. Life stages are age guidelines usually listed on bags of dry kibble along with corresponding feeding amounts. (These guidelines typically are not listed on canned food.) They’re broken down like this:

  • Puppy (up to age 1)
  • Adult (ages 1 to 6)
  • Mature (ages 7 to 11)
  • Senior (ages 11+)

Feeding guidelines printed on a bag of dog food are not a one-size-fits-all answer to how to feed your pet, however. Ask your veterinarian for specific recommendations, keeping in mind that as your dog ages his food needs will change.

If your dog needs to lose weight, the vet likely will recommend cutting back the amount of food he gets at each meal. (Once you settle on an appropriate amount, be sure to measure it out — don’t just estimate.) Or, your dog’s doc may suggest you try a reduced-calorie food. This can be tricky, because one brand of “diet” dog food may actually have more calories than another brand’s regular food. So when tweaking your pet’s feeding to help him slim down, the most important thing is to talk to your vet about the best approach to take.

Transition your pup to the new food slowly. Mix increasingly larger portions of the new food with the old over the course of a week or two until you’re feeding only the new food. Your dog is less likely to develop digestive problems this way.

How often. Most dog owners feed their dogs twice a day. “Put down the food bowl in the morning and in the early evening,” Ward says. “If your dog doesn’t empty it, take it away. Don’t leave out food for your dog to graze on.”

Keep a fresh bowl of tap water next to the food bowl. If you want to supplement your dog’s diet, talk to your veterinarian first about what to give and how much. (Ward gives his dogs lecithin and omega 3 fatty acids, which both support brain health.)

Related: 10 Foods You Should Never Feed Your Dog

If you have more than one dog. Keep their food bowls separate. Some dogs will quickly gobble down a meal and then push the other dog out of the way to steal a second helping. If you have to, serve up your dogs’ dinners in separate rooms with the doors closed. Don’t forget to pick up the food bowls when the dogs walk away.

Be careful about treats. It’s fine to offer your dog an occasional all-natural treat that lists meat as the first ingredient and that doesn’t have sweeteners, chemicals or artificial ingredients, says Ward. Most of the time, though, limit snacks to a small handful of raw vegetables — crunchy baby carrots, broccoli, peas or asparagus. They’re rich in nutrients and naturally sweet.

Walk it off

Exercise is an important part of losing weight and keeping it off. “Many people think that by letting their dog have access to the backyard the dog will get plenty of exercise,” says Ward. “It’s not true. When you first let your dog outside, he’ll probably run around. But after that he’ll likely find a comfy spot in the grass or retreat to his doghouse and sleep.”

Dogs are social animals and they need human interaction as well as plenty of exercise. Your pet should get three walks a day — in the morning, afternoon and before bedtime. Each walk should be at least 20 minutes long. Let him sniff and wander; talk to him as you move along. Walks should be fun for both of you — a chance to bond and get fit at the same time.

Related: Is Your Cat Overweight?

Michele C. Hollow writes about pets and wildlife. She is an award-winning journalist who has written for The New York Times, The New York Daily News, and other leading publications. She blogs at Pet News and Views.