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. doi: 10.2460/ajvr.73.7.1002.


Objective: To investigate the influence of dietary supplementation with l-carnitine on metabolic rate, fatty acid oxidation, weight loss, and lean body mass (LBM) in overweight cats undergoing rapid weight reduction.

Animals: 32 healthy adult neutered colony-housed cats.

Procedures: Cats fattened through unrestricted ingestion of an energy-dense diet for 6 months were 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 (unrestricted for 1 month, then restricted). Measurements included resting energy expenditure, respiratory quotient, daily energy expenditure, LBM, and fatty acid oxidation. Following weight loss, cats were allowed unrestricted feeding of the energy-dense diet to investigate weight gain after test diet cessation.

Results: Median weekly weight loss in all groups was ≥ 1.3%, with no difference among groups in overall or cumulative percentage weight loss. During restricted feeding, the resting energy expenditure-to-LBM ratio was significantly higher in cats that received l-carnitine than in those that received the control diet. Respiratory quotient was significantly lower in each cat that received l-carnitine on day 42, compared with the value before the diet began, and in all cats that received l-carnitine, compared with the control group throughout restricted feeding. A significant increase in palmitate flux rate in cats fed the diet with 150 μg of carnitine/g relative to the flux rate in the control group on day 42 corresponded to significantly increased stoichiometric fat oxidation in the l-carnitine diet group (> 62% vs 14% for the control group). Weight gain (as high as 28%) was evident within 35 days after unrestricted feeding was reintroduced.

Conclusions and clinical relevance: Dietary l-carnitine supplementation appeared to have a metabolic effect in overweight cats undergoing rapid weight loss that facilitated fatty acid oxidation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calorimetry, Indirect
  • Carnitine / pharmacology*
  • Cat Diseases / diet therapy*
  • Cat Diseases / metabolism
  • Cats
  • Dietary Supplements
  • Energy Metabolism / physiology
  • Fatty Acids / metabolism
  • Female
  • Male
  • Overweight / diet therapy
  • Overweight / metabolism
  • Overweight / veterinary*
  • Random Allocation
  • Statistics, Nonparametric
  • Weight Loss / physiology


  • Fatty Acids
  • Carnitine