Most of us are crazy about our dogs, and would love to have them by our sides as long as possible. We can’t control everything related to their health, but one thing we can for sure control is their weight. One study of Labrador Retrievers found that dogs that were kept lean lived an average of 2.5 years longer than their pudgy counterparts.

This shouldn’t be hard, right? Dogs can’t hit the drive-through at McDonald’s or order pizzas, so why is it that, according to the Association for Pet Obesity Prevention, 58% of American dogs are overweight or obese? Determining how to keep your dog trim and healthy can be difficult, but with a little knowledge, you can unlock an important mystery, and hopefully keep your best friend around for years to come.

Get educated about calories

Commercial dog foods vary widely in the amount of calories per cup of dry food. A quick Internet search for the caloric content of 5 popular adult dry dog foods produced an average reading of 369 calories per cup, but the range of calorie counts varied from 330 kcals/cup all the way up to 433 kcals/cup! And the range is even greater if you look at the so-called “pouch meals,” with some of those approaching 500 kcals/cup. So you can easily see that feeding “a couple of cups per day” without giving it more thought than that can get you and your dog into trouble.

Intelligent feeding practices will help to keep your dog at a healthy weight, and while that starts with understanding the amount of calories in his food, it continues with understanding his individual needs.

Understand how much food your dog truly needs

There is no cookie-cutter approach to figuring out how much food to feed your dog, although pet food manufacturers try to give guidelines on their labels. But those guidelines are typically ranges, both in terms of the size of the dog and the amount to feed. That’s because every dog metabolizes food differently, and because some dogs are more active than others.

Take an extremely popular grocery store brand of food. The label of “Brand X” recommends feeding dogs that weigh between 51 and 75 pounds 2 ¾ to 3 2/3 cups of food per day. For this particular food, that’s a range of 1191 to 1588 calories per day.

So how are you supposed to figure out how much food to feed your dog, with all of this confusing information? Your veterinarian can help, as he can calculate something called your dog’s “Resting Energy Requirement,” or RER. The RER is the amount of calories needed for a dog’s body to carry out the functions necessary for life, and it’s a somewhat crude starting point to help determine how many calories your individual dog needs per day to stay at a healthy weight. Different factors are multiplied by the RER to determine total calories, and these factors vary based on your dog’s activity level. So it follows that a working dog will have a much higher factor (2.0) than a couch potato dog (1.2), and will therefore need more calories.

Get some accurate feedback, and adjust

Not sure where your dog falls on the “couch potato” to “triathlete” scale? Tools like FitBark are invaluable for helping to determine just how active your dog is, on average, any day. Armed with that information, you and your vet can settle on the appropriate “factor” in order to determine your dog’s total daily caloric needs. And using FitBark allows you to pick up on changes in activity levels that could signal the beginning of a health problem, or simply a change in activity level that requires dialing back feeding amounts.

A cup is a cup is a cup

Once you understand your dog’s actual “food dose”, remember that “a cup” means one measuring cup, not enough food to fill up the Big Gulp cup you brought home from your last road trip. It also means “one level cup,” so take care to measure accurately and without heaping more food than necessary into your measuring cup.

Use an actual measuring cup to portion your dog’s food, and measure accurately every time you feed your dog.

Treats are called that for a reason

There is no requirement that the manufacturers of foods labeled as “treats” report their caloric content. So you’ll get very little guidance from the packaging on these products, however they can be a significant source of additional calories in your dog’s diet.

If possible, limit treats in your dog’s diet, and choose healthy alternatives, such as baby carrots, so that you know how many calories are going in. And don’t forget that if you’re giving treats, ideally you’d be reducing the total volume of “regular” food being fed to compensate.

Have a family meeting

Dogs and kids go hand in hand, but kids can contribute significantly to the amount of food that a dog gets every day, and often without the knowledge of the adults in the house. What dog hasn’t learned that the spot directly under the kid’s chair is the best spot to perch at dinnertime?

Talk to your kids about how important it is to control your dog’s food intake. Explain that being fat will make their beloved pet prone to serious diseases, and reduce his lifespan. If your kids are too young to understand, put your dog in another room during family mealtime, and make sure to keep the kids’ snacks in the kitchen and out of reach of questing noses.