By Dr. Becker
A study conducted last year at Cornell University’s College of Veterinary Medicine suggests cats on weight loss programs can benefit from L-carnitine supplementation1.
The goal of the study was to investigate the effect of L-carnitine on metabolic rate, fatty acid oxidation, lean body mass, nitrogen balance, and net weight loss on healthy overweight cats undergoing rapid weight loss.
As it turns out, L-carnitine doesn’t actually promote weight loss. Its advantage is in its helpful metabolic effects on kitties.
Study Involved 32 Healthy Adult Cats
In the first phase of the study, 32 healthy adult cats were fed unrestricted amounts of a high calorie diet for six months.
In the next phase, the cats were separated into four groups of eight and fed a low calorie diet (unrestricted for four weeks, then restricted for the remaining eight weeks). One group received no L-carnitine supplementation; one group received 50 mcg (micrograms) of L-carnitine per gram of diet; the third group received 100 mcg per gram and the fourth group received 150 mcg.
Each week the cats’ weight, body condition score and dietary intake were measured. Median weight loss was ≥ 1.3 percent per week in all four groups.
Metabolic responses, including resting energy expenditure and daily energy expenditure were also measured at the beginning of the study and at days 42 and 84.
Cats Receiving L-Carnitine Had Improved Metabolism
During the restricted feeding period:
- The resting energy expenditure-to-lean body mass ratio was significantly higher in cats that received L-carnitine supplementation.
- The respiratory quotient was significantly lower in cats that received L-carnitine on day 42 than it was at the start of the study, and was lower in all cats receiving L-carnitine compared with the group that was not.
- Also on day 42, there was a significant increase in palmitate flux rate in cats receiving 150 mcg of L-carnitine compared to the group not receiving the supplement, as well as significantly increased fatty acid oxidation at 62 percent for cats receiving L-carnitine compared to 14 percent for the cats that were not.
At the end of the 12-week study, unrestricted feeding was reintroduced and weight gain as high as 28 percent among the cats was evident in just over a month.
L-Carnitine May Help Heavy Cats Lose Weight Safely
These study results indicate that while L-carnitine doesn’t play a direct role in helping heavy cats lose weight, it does produce several positive metabolic effects that may help prevent the development of hepatic lipidosis (fatty liver disease) in kitties that are being dieted down to a healthier weight. In the study, L-carnitine supplementation increased fat oxidation and decreased carbohydrate metabolism, which fits well with the natural metabolism of felines.
While the goal of the Cornell study was to test the effects of L-carnitine on cats undergoing the equivalent of a crash diet, I don’t recommend fast weight loss for kitties, regardless of whether L-carnitine is supplemented. The risk of hepatic lipidosis is significant, and I can’t think of too many situations in which there would be a practical need to crash diet a cat.
There might be the rare instance where a kitty needs important surgery but is too overweight to risk it, in which case an aggressive weight loss program might be attempted. But barring situations of that nature, I always recommend slow weight loss for cats.
For detailed instructions and tips on how to get your own kitty down to a healthy weight safely and successfully, check out my video and article titled Valuable Tips for Helping Your Heavy Cat.