By Dr. Becker
If you're a regular reader here at Mercola Healthy Pets, you've undoubtedly run across a few of the many articles I've written about the epidemic of obese pets in the U.S. In 2012, over half of all dogs were overweight or obese, and almost 60 percent of cats were as well.
I've also written extensively about the right and wrong way to help your pet lose weight, and I always caution against commercial "weight loss" pet food formulas with dodgy ingredients, as well as other pet weight loss gimmicks. So when I saw an article recently in a veterinary industry publication about the success of yet another new "prescription" pet weight loss diet, I had to investigate.
2012 Feeding Trial of New 'Prescription' Weight Loss Pet Food
In 2012, the manufacturer of a new prescription weight loss diet for dogs and cats conducted a veterinarian-supervised blinded feeding trial involving 314 overweight cats and dogs in the U.S. and Canada. The study was designed to determine if pets would lose weight even if their owners didn't know they were participating in a weight loss study.
The study included 159 dogs across 58 breeds that weighed between 5.5 and 249 pounds. There were also 155 cats representing eight breeds, and weighing from 9.5 to 27 pounds.
All the pets were weighed, measured, and started on the new weight loss food. After two months on the diet, 96 percent of the dogs and 81 percent of the cats had lost weight according to the pet food company. The animals had an average reduction in body fat of 28 percent during the two-month trial.
Based on these results, the owners of the dogs and cats agreed to continue to feed the diet and have their pets weighed and examined every month by their vet. The owners also completed surveys, and 68 percent felt it was an easy way for their pet to lose weight. Sixty-five percent believed the food kept their pet feeling full, and 80 percent would recommend the food to friends with overweight pets.
A Closer Look at the Ingredients in the New Weight Loss Formulas
Here are the first 10 ingredients in the dry dog food formula:1
Chicken By-Product Meal Soybean Mill Run Whole Grain Wheat Soybean Meal Whole Grain Corn Dried Tomato Pomace Corn Gluten Meal Chicken Liver Flavor Pea Bran Meal Dried Beet Pulp
And here are the top 10 ingredients in the canned cat food formula:2
Water Corn Starch Pork Liver Chicken Pork By-Products Flaxseed Corn Flour Tomato Pomace Powdered Cellulose Natural Flavor
All the formulas contain added L-carnitine, which, according to Veterinary Practice News, "help a pet burn excess body fat and spare lean muscle mass without depriving pets of needed daily caloric intake."
Dogs and cats in the wild obtain L-carnitine from real food (prey), and their bodies are also able to synthesize it from the essential amino acids lysine and methionine. The food source richest in L-carnitine is red meat, followed by chicken, pork, poultry, fish and dairy products. Plant foods – vegetables, fruits and grains – contain insignificant amounts.
When you look at the lists of top 10 ingredients above, it becomes clear why it's necessary to supplement the formulas with L-carnitine and other amino acids. It's because the food lacks the type and quality of meat-based protein dogs and cats require.
Marketing Hook: A 'Scientifically Formulated Nutrient Complex' That Encourages Fat Burning
A press release from the manufacturer claims the new weight loss pet food:
"…uses a scientifically formulated nutrient complex that works with each pet's unique energy expenditure to encourage fat burning while sparing lean body mass, by up-regulating or down-regulating certain gene expression. This switches obese and overweight pets to a gene expression profile usually associated with lean animals."
After a careful review of the entire list of ingredients in the new food, I suspect the "scientifically formulated nutrient complex" referred to in this statement is simply supplemented essential amino acids found in animal meat. When dogs and cats eat the food they are designed to eat in appropriate amounts, they naturally burn fat, preserve lean body mass, and maintain a gene expression profile associated with lean animals.
The press release also states that once pets have lost the required amount of pounds (or ounces), they can be fed up to 50 percent more of the same food and still maintain their target weight. This equates to "weight maintenance without food deprivation," which is "a common cause of owner complaints."
So not only has the manufacturer developed a pet food formula that results in significant and fast initial weight loss – they've also figured out how to create customers for life. I've got to hand it to them.
With all that said, I would never recommend this "prescription" weight loss food for dogs or cats.
A Much Healthier Approach to Dieting an Overweight Pet
In my experience, the vast majority of overweight cats and dogs are one or more of the following:
- Eating a processed, biologically inappropriate diet
- Are overfed
- Are offered too many high calorie treats
- Aren't getting enough physical activity
Also in my experience, the long-term solution is not to replace one processed pet food with another processed pet food, even one containing a magical "scientifically formulated nutrient complex" for weight loss. Unless, of course, the only goal is to get the weight off by any means possible, as quickly as possible.
I recommend a more holistic approach aimed at improving an animal's overall health and vitality for the long haul, while simultaneously encouraging weight loss. It's a three-pronged approach, and it's not complicated. But it does require a bit more time and effort, and perhaps expense, than opening a bag or can of processed pet food.
- Transition to a balanced, species-appropriate diet. Skip all the commercial and prescription weight control and low fat diets. Regardless of her weight, your dog or cat still needs the right nutrition for her species, which means food that is high in animal protein and moisture, with low or no grain content.
- Practice portion control -- usually a morning and evening meal, carefully measured. A high protein, low carb diet with the right amount of calories for weight loss, controlled through the portions you feed, is what will take the weight off your dog or cat. And don't forget to factor in any calories from treats.
- Regularly exercise your pet. An overweight body gets back in shape by taking in fewer calories and expending more energy. Daily exercise, including at least 20 minutes of consistent aerobic activity, will help your pet burn fat and increase muscle tone.
Below are before and after pictures of my patient, Cal. Cal was a rescue who was obese and depressed at the time of his adoption by one of my clients. Most of the pet owners in my practice feed some variation of a raw or homemade real food diet. Cal's new mom transitioned him to a commercially available, balanced, species-appropriate raw food diet, and he dropped the weight on his own once he was eating the right kind of food.
Cal will spend the rest of his life eating a fresh, natural, meat-based diet. Those 159 dogs in the weight loss study will likely spend the rest of their lives eating a highly processed food made with low grade ingredients like chicken by-product meal and assorted cheap, low quality fillers.
Which would you choose for your pet?