Hi stranger! Signing up for MypetMD is easy, free and puts the most relevant content at your fingertips.

Get Instant Access To

  • 24/7 alerts for pet-related recalls

  • Your own library of articles, blogs, and favorite pet names

  • Tools designed to keep your pets happy and healthy

or Connect with Facebook

By joining petMD, you agree to the Privacy Policy.

petMD Blogs

Written by leading veterinarians to provide you with the information you need to care for your pets.

Nutrition Nuggets is the newest offshoot of petMD's Cat Nutrition Center. Each week Dr. Coates will use her expertise and wisdom to blog about the intricacies of cat nutrition.

No Quick Fix for Overweight Cat

May 03, 2013 / (1) comments

I had a case a few years ago that still nags at me. My patient was (shall I just be blunt?) fat. Oscar was an affable orange tabby. He weighed 17 pounds and should have tipped the scales at about 11. His owner had recently moved to town and was looking for help getting Oscar to lose weight.

Over the course of almost a year, we tried everything I could think of including at least three different diets, dramatic alterations to the amount of food that was offered, different feeding schedules, increasing exercise, and environmental enrichment. All to no avail; Oscar’s weight didn’t budge. If he dropped a few ounces in April, he rebounded in May.

I was (and still am) convinced that Oscar had to be eating something in addition to what I was prescribing, but his owner insisted this was not the case, at least as far as she was aware. In the end we simply threw up our hands and accepted defeat. Oscar’s owner went back to free feeding him and at his next wellness exam he weighed (drum roll please) 17 pounds.

I’m always on the lookout for any information that could help cats like Oscar. I came across a potentially promising study that looked at whether or not the dietary supplement L-carnitine, an amino acid, could help cats lose weight. You’ve probably heard of L-carnitine. It’s all the rage in bodybuilding circles. On the veterinary front, deficiencies have been associated with dilated cardiomyopathy (a type of heart disease) in cats and certain breeds of dogs. Some pet food manufacturers have started adding L-carnitine to foods asserting that it helps maintain cardiac health and lean body mass and can promote weight loss.

These claims are not without merit. L-carnitine moves fatty acids through the membrane that surrounds mitochondria in cells. Mitochondria produce energy, so it makes sense that an ample supply of L-carnitine is necessary to efficiently convert fatty acids into energy. It doesn’t necessarily follow, however, that L-carnitine supplements will help cats lose weight, and that, unfortunately, is the conclusion that this study reached.

hirty-two healthy, neutered cats were “fattened through unrestricted ingestion of an energy-dense diet for 6 months.” They were then “randomly assigned to 4 groups and fed a weight reduction diet supplemented with 0 (control), 50, 100, or 150 μg of carnitine/g of diet.”

All groups lost weight, but there was “no difference among groups in overall or cumulative percentage weight loss.” The study did find some metabolic differences between the cats that received L-carnitine and those that did not. Therefore, it looks like supplementation might help cats lose weight in a healthier manner, just not any quicker than they would otherwise.

That’s something — even if L-carnitine isn’t a panacea that can help cats like Oscar. Check out today’s Nutrition Nuggets for dogs for more information on the dilemma surrounding overweight pets.

Dr. Jennifer Coates


Center SA, Warner KL, Randolph JF, Sunvold GD, Vickers JR. Influence of dietary supplementation with (L)-carnitine on metabolic rate, fatty acid oxidation, body condition, and weight loss in overweight cats. Am J Vet Res. 2012 Jul;73(7):1002-15.

Image: Otmar Smit / via Shutterstock