Based on an article that first appeared at

For those of you who have not already received the lecture from your veterinarian about the danger your pet’s obesity poses to his/her health, I am happy to fill that role in this post.  Diseases both caused by and exacerbated by obesity include degenerative joint disease, degenerative disk disease of the spine, diabetes, pancreatitis, hypertension, cardiac disease, and pulmonary (lung) disease to name some.  While owner refusal to stop overfeeding or augmenting the dietary regimen with food from the table are by far the most common reasons for persistent obesity, there are some isolated cases of pets that despite the owner’s best efforts and vigilance in feeding only the recommended prescription weightloss diet in the right quantities, still lose weight painfully slow, not at all, or in some cases even put on weight.

Traditionally, we have had two main approaches to weightloss diets in dogs and cats.  Initially, we treated both dogs and cats the same, recommending dietary formulations that were high in fiber and complex carbohydrate, normal protein, low in simple carbohydrate, and low fat.  These diets essentially were designed to fill the tummy while at the same time restricting calories.  In dogs, these diets were met with reasonable success in effectively dropping body fat and excess weight when properly adhered to, while in cats results were widely varied and inconsistent.

While our approach to canine weightloss dietary concerns have remained by in large unchanged, a more recent movement in feline weightloss diets that became popular in the early to mid-2000s was to formulate ultra-low carbohydrate, high protein diets.  These diets were created on the premise that domestic cats are likely so obese because in a domestic setting we feed them a carbohydrate laden diet that is not consistent with the manner in which they evolved as pure carnivores.  In reality, cats can synthesize any nutrient they need effectively from protein, making them very different from dogs and people, which are omnivores, necessitating the consumption of a diet of mixed nutrients which provide certain proportions of fats, simple and complex carbohydrates, and protein.

Thus diets like Hills M/D and Purina DM were created and to this day remain popular diets among veterinarians for weight and body fat reduction, as well as diabetes management in cats.  But there are still a frustrating number of cats who do not lose any weight being fed these diets exclusively, and even some that get fatter on them, my own cat included!  What’s more, we are stumped as to why this is the case for some feline patients.

The latest innovation in weightloss works very differently than any other weightloss diet on the market.  Hills Metabolic prescription weightloss diet works by actually increasing the pet’s basal metabolic rate, thus increasing the rate at which they burn calories.  When this diet was set to be released, the Hills corporation provided veterinarians statistical data that spanned 5 years of research and numerous feeding trials that showed that 88% of dogs lost an average of 28% body fat within 2 months; and the same percentage of cats lost 29% of the body fat in the same time frame when fed this diet exclusively.

With no other weightloss diets to date having been able to claim this level of success before, my first reaction was one of skepticism.  While the Hills Corporation does an impressive level of ongoing research for their diets, the data they provided for Hills Metabolic just seemed too good to be true.  Subsequently, when my Hills rep noted my skepticism, she answered it by offering me 400 pounds of food to give away to my most frustrating obesity cases.

The first patient I tried it on, is a 12 year old Shetland Sheep Dog that was not only obese, but under treatment for debilitating thoracolumbar intervertebral spinal disease.  She was about 20 pounds overweight, which for this breed is a severe level obesity under which her spine and her joints were simply being crushed under.  At one of her therapy appointments, I suggested to the owner that she try the free Metabolic samples Hills had provided us, to which she agreed.  Once month later, the dog had lost 11 pounds, given her history, nothing short of miraculous.  Since then, she has dropped an additional 7.  As a result, her back is doing phenomenally well, but the most impressive part is that her owners report a new lease on life, with more spunk and energy, like we literally turned back the clock 5 years on the dog.

Since I started carrying Hills Metabolic earlier this year, I have seen several other similar success stories in both dogs and cats to date, but with still a relatively small case number, it remains premature for me to draw definitive general independent conclusions.  However, while it is too soon for me to necessarily sing its praise as the next great innovation in canine and feline obesity management, I do not hesitate to recommend Hills Metabolic Diet for severely obese pets whose diseases are debilitating and directly tied to their obesity, hence necessitating weightloss in as timely a fashion as possible.

Dr. Roger Welton is the President of Maybeck Animal Hospital and CEO/Chief Editor of the veterinary information and blog online community, Web-DVM.