Definition of Obesity

Obesity is considered to be the most common form of malnutrition in small animal practice. It has been suggested that as many as 40% of pets are obese. The significance of obesity pertains to its role in the pathogenesis of a variety of diseases and the ability to exacerbate pre-existing disease. Obesity has been associated with an increased incidence of osteoarthritis, cardiorespiratory problems, diabetes mellitus, constipation, dermatitis, anesthetic risk, and reduced life-expectancy.

Alex GERMAN
BVSc (Hons), PhD, CertSAM, Dipl. ECVIM-CA, MRCVS

Alex German qualified, with honors, from the University of Bristol in 1994. He then worked for two years in mixed practice before returning to Bristol to undertake a PhD and then residency in small animal internal medicine. He was awarded the RCVS certificate in small animal medicine in August 2001. In October 2002, he moved to Liverpool University, and is currently the Royal Canin Senior Lecturer in Small Animal Medicine and Clinical Nutrition. In September 2004 he became a Diplomate of the European College of Veterinary Internal Medicine. His current research interests include small animal gastroenterology, metabolomics, and obesity biology.

Lucile MARTIN
DVM, PhD

Lucile Martin graduated in 1990 from the National Veterinary School of Nantes (ENVN), where she is now Senior Lecturer at the Nutrition and Endocrinology Unit. After obtaining her PhD in nutrition in 1996, she took charge of a research program on butyrate metabolism and inflammatory bowel diseases at the Human Nutrition and Research Center of Nantes. Since 1999, Lucile has also participated in diagnosis and research with the ENVN LDH (Hormone Assay Laboratory) to study endocrine disorders linked with obesity in domestic carnivores. In January 2001, she was elected to the Board of the AFVAC Dietetic Study Group. In addition to teaching clinical nutrition for pets and horses and acting as a consultant in nutrition and endocrinology at the Veterinary School of Nantes, Lucile is the author of more than 30 publications on research and continuing education.

1. Definition of Obesity

Obesity is defined as an accumulation of excessive amounts of body fat (Bray, 1999). In humans, a wealth of epidemiological data demonstrate that morbidity and mortality risk correlates with increasing body fat mass. Criteria are usually based on indirect measures of adiposity such as the body mass index (BMI; weight [kg] divided by height2 [m]), and definitions exist for "overweight" (25 < BMI < 30 kg/m2) and "obese" (BMI > 30 kg/m2). A recent large-scale epidemiological study suggested that the optimal BMI for non-smoking 50 year-old adult Caucasians was 20 - 25 (Adams et al., 2006), and many other studies concur with these findings. In contrast, data on what represents an optimal feline body weight are more limited; cats are classified as being overweight when their body weight is more than 10% above their "optimal body weight", and classified as "obese" when their body weight exceeds 20% of optimal (Lund et al., 2005). In the largest epidemiological studies of their kind, increasing risk of associated diseases is seen with increasing levels of adiposity, as judged by body condition score (BCS) (Scarlett et al., 1998, Lund et al., 2005). This suggests that, like in humans, excessive weight confers a mortality and morbidity risk (see below) and support the need to strive for optimal body condition.

Overweight or Obese?

Cats are classified as being overweight when their body weight is more than 10% above their "optimal body weight", and classified as "obese" when their body weight exceeds 20% of optimal.