This is a tough question; a really tough one for a great many of my clients. But it’s not rocket science, so here’s my simple prescription:

If your pet is overweight, reduce the amount you feed her by a teensy bit every week until you can see the pounds start coming off. Maintain this food volume until she has reached a normal weight. Once she has, you might find that giving her a little more is OK. And voilá! You now possess a bona fide veterinarian-approved diet.

Some pets require more exercise, some less. Some demand extra attention to detail (fat cats, for example, should not lose weight too precipitously). But all healthy pets — without exception — have the capacity to attain normal weights on this simple calorie-restricted regimen.

As for so many popular human diets that rightfully claim effectiveness, many pet food companies claim that weight loss will be best achieved by feeding their "specially formulated" diet. And they may be right. But I find it’s way simpler to stick to the concept of "calories in = calories out."

Which means that the amount of calories an animal consumes must equal the amount of calories the animal expends — that is, if weight maintenance is desired. If weight loss is the goal, calories in must be less than calories out.

Makes sense, right? And yet it’s not so intuitive. Why? Because nothing rational stands up to this common utterance: "But she’s so hungry all the time!"

At this point, it’s my role to calmly explain that the notion of "hunger" is something they should probably re-examine. Because being "hungry" is a very different thing from wanting food.

We can all glean these basics from our own personal experience: Food tastes good, so we eat more. And we "overdo it" a lot (take, for example, next week’s Thanksgiving festivities). We even experience severe, life-threatening effects related to our overindulgence. Yet, we continue to eat more.

From the medical point of view, we’ve also come to the understanding that a barrage of hormones are released when we’re hungry, when we smell food, and then when we eat it — all of which affects our total caloric intake.

When we eat, hormones are released, letting our body’s key stakeholder parts know that we’re full-up and can stop eating. But if we eat too fast our hormones don’t get the chance to deliver the memo in time. So we keep eating. And it seems that the memo can be similarly delayed when we consume certain kinds of food. So we keep eating … until the message gets through.

Alternatively, another memo may be responsible for requesting greater intakes of food. But science-wise, we’re still kind of fuzzy on these hormonal messages and their triggers. Otherwise, we might actually have a fighting chance at curbing the obesity epidemic a bit better than we’re currently managing.

In the absence of clear directives, I’ll admit it can all be a bit confusing. Yet the upshot should be obvious: As a culture, we Americans are a whole lot less "hungry" than we think we are — which really should help inform how we treat our pets. And yet, we clearly share a collective interpretation of our pets' hunger. Otherwise they would not be tipping the scales as they are in ever increasing numbers.

Yes, a full 50 percent of our pets are overweight or obese, according to the Association for Pet Obesity Prevention. And is it any wonder? After all, our pets seem to be well aware of the old biblical adage that those who demand will be rewarded with greater spoils for their trouble. And since food = love for so many U.S. households, this hungrified pet trend is showing no signs of abating.

Dr. Patty Khuly