About half of U.S. dogs and cats are overweight, and a third of dogs visiting the vet in the last decade were clinically obese. As is the case with humans, obesity affects both the quantity and quality of life pets enjoy.
Pet obesity is a serious health threat. There are several common disorders and diseases directly attributable to obesity, including:
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There are a number of contributors to obesity. For example, it is suspected but not proven that certain breeds are predisposed to obesity. However, a clear link has been established between neutered dogs and overweight, and the same is presumed to be true for cats.
In fact, a study with Beagles showed after neutering the dogs needed a 30 percent decrease in calories or an equivalent increase in activity in order to maintain a healthy weight.
The hormone leptin is also a major factor in obesity. Leptin acts on reproductive and immune functions and also on insulin sensitivity.
Leptin binds to receptors in the brain that are directly related to appetite suppression. Overweight people and pets have high circulating leptin levels, so it is not a lack of the hormone that is the problem, but the inability of leptin to act on the hypothalamus in overweight animals. Animals are becoming as leptin-resistant as people.
Another hormone important in obesity is adiponectin. Adiponectin enhances insulin sensitivity and increases glucose uptake. Low levels of this hormone are associated with type 2 diabetes, insulin resistance and high blood pressure in humans. While the same connection has not yet been established in companion animals, it is a fact that obese dogs and cats have decreased levels of adiponectin.
According to Clinician’s Brief:
Management of weight issues in pets is complicated by the human–animal bond. The increase in obesity of pets is increasing as human obesity increases in the population. Most veterinarians would agree that it can be very awkward to discuss a pet’s weight issue if the owner has a weight issue.
The Clinician's Brief article primarily addresses metabolic aspects of obesity, while the Live Science article discusses the fact that dogs and cats aren’t the only animals growing fatter over time.
A weight gain study wrapped up recently at the University of Alabama, Birmingham, involving over 20,000 individual animals across eight species and 12 distinct populations, specifically:
- Laboratory macaques, chimpanzees, vervet monkeys and marmosets
- Laboratory mice
- Domestic dogs and cats
- Domestic and feral rats from both rural and urban areas
The result? Weight increased for both genders across all species and populations. Study results reported in the journal Proceedings of the Royal Society B include:
- Weight increased in macaques by 7.7 percent per decade for males and 7.9 percent for females
- Male mice grew 10.5 percent heavier and female mice 11.8 percent heavier per decade
- Female cats showed a weight increase of 13.6 percent per decade; male cats grew 5.7 percent larger
- Dogs added 2 to 3 percent to their body weight per decade
- Male feral rats in Baltimore grew 5.7 percent per decade; females by 7.2 percent
- Rural rats also showed increases
What the Heck is Going On?
The University of Alabama study seems to indicate there’s more going on with the steadily increasing size of animals on the planet than a simple formula of energy intake vs. energy output.
The LiveScience article suggests additional contributors might include:
- Adenovirus 36. A significant number of obese children test positive for this viral infection.
- Exposure in utero to hormone-disrupting compounds has been shown to trigger obesity in mice. These endocrine disruptors are typically xenoestrogens – estrogen mimicking chemicals found in fertilizers, pesticides, soil, non-organic meats, and plastics.
- Light pollution and sleep disruption.
- Artificial environments. David Allison, the University of Alabama, Birmingham’s lead study researcher, explains it this way: "In the winter, you're not expending as much energy, because the room is kept warmer. In the summer, it doesn't get so hot, and we know that heat drives food intake down."
According to Jennifer Kuk, an obesity researcher at Toronto’s York University who was interviewed by Live Science for their article:
“If the number of calories going in is the same over time, and there's a net gain, then obviously the way those calories are managed is different or something has changed. Why that management of calories is changing is going to be important if we're going to reverse the trends."
So Is My Pet’s Weight Something I Can Control?
You bet it is!
It’s important for us to learn as much as possible about potential contributors to obesity – especially those unrelated to overeating and a sedentary lifestyle.
But no matter what other reasons there might be for obesity, the primary cause for the vast majority of us will remain the same: too many calories consumed and too few burned. It’s a simple fact of life -- the right foods in the right amounts coupled with consistent calorie-burning physical activity, is the best way to maintain a healthy weight.
It’s important to be mindful of the fact your pet is entirely dependent on you for what and how much he eats, and whether he’s physically active enough to stay in good shape. So not only is your dog’s or cat’s weight and overall condition within your control, it’s your responsibility.
Do’s and Don’ts for Keeping Your Furry Friend Fit and Trim
DON’T feed your pet an all-day all-she-can-eat-buffet. In order to take weight off your cat or dog and keep it off, you must feed controlled portions – usually a morning and evening meal, carefully measured.
DO make sure your pet is adequately exercised on a consistent basis. Your dog or cat needs to elevate his heart rate for a minimum of 20 minutes several times a week in order to move his body into a fat-burning state. There are any number of physical activities you can involve your dog in, even during the long, cold winter months. It’s just as important to get overweight kitties moving.
DON’T believe the marketing claims of ‘low fat’ commercial pet foods. These formulas are full of carbs and fiber – exactly what your pet’s body doesn’t need.
DO factor treats you feed your pet into the daily calorie plan. Keep in mind pre-packaged commercial treats are a primary reason for excess weight in many pets. These snacks are loaded with carbs, sugar and fat and are specifically designed to create intense cravings in your dog or cat.
DO partner with an integrative or holistic veterinarian to design a weight loss plan customized for your dog or cat, and take your pet for regular wellness visits to manage her weight and her overall health.