Editor’s note: Tomorrow (Oct. 8) is National Pet Obesity Awareness Day, so we’re republishing this post on the subject from Dr. Barchas so that you can refamiliarize yourself with the issue and comment on the post.

Someone recently asked me about obesity in dogs. In recent years (if you count the last 20 years at least as recent), we’ve seen a great hype about the canine “obesity epidemic.” Dogs, it is said, are keeping pace with humans in the field of ever-growing waistlines. And, like humans, they are suffering the consequences.

But is it true? Is obesity becoming more prevalent in dogs? Is obesity sickening them? If so, what can be done about it? And how can you tell if a dog is fat, anyway?

Let’s deal with the last question first. Human medicine attempts to use quantitative scientific methods of defining obesity. The current methode de rigueur is the body mass index, or BMI. The use of the BMI enables scientists, physicians, journalists, and alarmists to plot nice charts detailing the prevalence of obesity over time; the current trend line indicates that the obesity rate will eventually rise to 500 percent of all Americans.

Measurement of obesity in dogs is subjective. Veterinarians have been trained to assess dogs’ weight status using the body condition score. This so-called BCS was invented in part, I believe, so that clients would not be able to read a veterinary chart and realize that the vet had deemed their dog fat. It is also a pseudoscientific attempt to quantify obesity — but since the scale is subjective, it by definition cannot be quantitative. Adding insult to the injury of the scale’s subjectivity is the fact that there are two competing scales. One of them is a five point scale in which a score of one is terribly emaciated, three is perfect, and five is markedly obese. In the other, a nine-point scale, one is emaciated, five is perfect, and nine is markedly obese. Many vets write a body condition score on a chart without indicating which scale they have used; I have sometimes seen charts that read, “BCS = 3” and don’t know whether at that time the dog’s weight, in the opinion of the veterinarian, was low or perfect.

The subjectivity of the body-condition score scales really shows through with regional differences; a dog with a weight deemed perfect in St. Louis may be deemed overweight in Los Angeles. I kid you not.

Anyhow, body condition scores are irrelevant. Obesity is actually simple to define: It is a condition of excess weight that causes morbidity. Morbidity means adverse effects on health.

Body conformations in dogs vary greatly, so it can be challenging to look at a dog and determine whether his weight is healthy. However, in general, if your dog’s weight is healthy you will be able to feel his ribs and his spine but the bones will not be prominent. There will be a “waist” in which the dog’s body narrows between his ribs and his hips. And his abdomen will “tuck” — in other words, when standing his chest will be closer to the ground than his tummy.

In practice a person needs to have experience with many dogs before one can determine whether a dog is overweight. But once you are sufficiently familiar with dogs, obesity becomes like pornography (with apologies to Potter Stewart): You know it when you see it.

Is obesity becoming more common in dogs? Because of the subjectivity of the methods used to assess canine weight, it is impossible to say. However, in my experience the answer is no. I believe that awareness of obesity in dogs is increasing. But, if anything, obesity in dogs appears to be decreasing, in my experience. I feel (again, subjectively), that I see far fewer obese dogs now both in practice and on the streets than I did 10 years ago.

However, obese dogs still exist. And they do, in many instances, suffer from health effects from their weight status. Obesity contributes to and exacerbates a number of health problems in dogs, such as heart failure, bronchitis, collapsing trachea, laryngeal paralysis, skin infections (due to inability to groom and excess folds of skin), and bladder infections.

Obesity takes its biggest toll on dogs’ mobility. Overweight dogs are far more likely to show symptoms of arthritis, and the arthritis itself may progress faster, due to the excessive strain that extra weight places on the joints. They are more likely to show the effects of luxating patella and hip dysplasia. Sadly, since mobility problems are a leading cause of deteriorating quality of life among large breeds of dogs, obesity can in some instances contribute to the decision to perform euthanasia.

Furthermore, obese dogs do not get to enjoy the pleasures of activity in the same way as their skinnier counterparts. Taking a walk is among my pal Buster’s greatest joys of the day. Many obese dogs do not enjoy walks in the same way (although some can rightfully argue that this might be a chicken-and-egg dilemma when it comes to cause and effect).

What can be done about canine obesity? In most cases, plenty. The first step is to rule out medical problems, including glandular conditions such as thyroid disease and Cushing’s Disease, which contribute to obesity. The next steps are the same as they would be for any individual who is trying to lose weight and keep it off: permanent lifestyle change.

Skip the fad diets (yes, they exist for dogs), and go straight to what has always worked best. Offer your dog fewer calories, and offer him more opportunities to burn those calories. I am happy to say that the first step, offering fewer calories, is much easier for dogs than for humans. We control how much they eat, so they needn’t exercise willpower to lose weight. However, we must exercise willpower for our dogs to lose weight, since it can be hard to ignore a dog’s begging eyes.

Treats are prime offenders in the world of canine obesity. Half a hot dog fed to a Chihuahua is the equivalent of six to eight hot dogs in a human. Most treats aren’t labeled with caloric information, but many of them are highly fattening. Cutting back on treats and switching to lower calorie alternatives such as pieces of carrot (which most dogs love as much as any other imaginable treat) is one way to fight obesity.

Smaller meals and more walks round out a simple weight loss plan for an overweight dog. And don’t forget that those walks aren’t just good for the dog — they also offer plenty of social and physical benefits for the person holding the leash.

Got a question for Dr. Barchas? Ask our vet in the comments below and your topic might be featured in an upcoming column. (Note that if you have an emergency situation, please see your own vet immediately!)

Read more by Dr. Eric Barchas:

• Why Do Some Dogs Keep “Showing Their Lipsticks”?
• Let’s Talk About Dogs and Euthanasia: When Is It Time? Should You Be Present?
• What to Do Before You Get to the Vet in 12 Emergency Dog Situations
• 12 Dog Emergencies That Need Immediate Veterinary Attention
• Just How Dangerous Is It to Falsely Call a Pet a Service Dog?