“ARE vets to blame for the epidemic of pet obesity?” was the question raised by Dan Chan at the London Vet Show last month. Mr Chan is senior lecturer in emergency and critical care and head of the Nutritional Support Service at the RVC.
He said that despite all the awareness campaigns, weight control clinics, specialist diets, and so forth, the prevalence of pet obesity was increasing and showing no sign of abating.
Those searching for the cause of the problem focused almost entirely on “client compliance” but, he asked, has the profession been effective? He believed it could be worthwhile for the profession to reflect and identify ways in which pet obesity could be managed more effectively as it was clear that so far little impact has been made.
Recent research, Dan said, had suggested a mechanism for the link between excess body-weight and various inflammatory conditions. The persistent low-grade inflammation secondary to obesity is thought to play an important role in the pathogenesis of chronic diseases such as osteoarthritis, cardiovascular disease and diabetes mellitus. Obesity was also associated with increased oxidative stress.
Many factors play a role in the development of obesity, he said, and its prevention relies on understanding the contributing or associated risk factors and managing them appropriately.
Important risk factors included neutering, over-feeding and inactivity. Neutering could significantly reduce maintenance energy requirements but also increase spontaneous food intake, so recommendations to deal with it had to include controlling food intake. Every practice should emphasise this to clients when discharging patients after neutering, Mr Chan said.
He commented that one of the major problems pet owners cite is that advice given to them about feeding is very generic and non specific. An instruction such as “follow instructions on food label” is frequently inadequate and ineffective. Most vets shy away from being specific, especially about calorie requirements and how this equates to quantities of food, and this might be the start of the problem.
Consistent calculation ‘often overlooked’
Consistent calculation of energy requirements for individual pets is often overlooked, but while it is calorie restriction that ultimately induces weight loss, it is important to avoid excessive reduction of other essential nutrients. An important goal for weight loss is to promote loss of fat while keeping loss of lean tissue to a minimum.
Mr Chan mentioned that several studies in humans had shown that diets very low in carbohydrates could lead to weight loss and although there were anecdotal reports that this might work in overweight cats, there were limited data to support such an approach.
It is clear, he said, that effective and sustained weight loss is not achieved in many overweight and obese animals and new approaches should be explored to deal with cases where conventional approaches are not working.
He went on to list a number of “newer concepts”, such as increasing dietary protein, often in place of carbohydrates, and the use of pharmacological agents to curb appetite or inhibit nutrient intake.
“As poor owner and patient compliance is one of the most common reasons for weight loss programme failures in cats and dogs, strategies that produce noticeable results are needed to improve compliance.”
Noting that two drugs were currently licensed for weight loss in dogs, Mr Chan said the MTP (microsomal triglyceride transfer protein) inhibitors had been developed as inhibitors of fat absorption and appetite suppressors. The use of these MTP inhibitors might achieve sustained weight loss in certain animals that had failed to lose weight using conventional methods.
The advantage of appetite-controlled weight loss over fat malabsorption is that fewer adverse events associated with poor faecal quality, steatorrhoea or the potential for malabsorption of fat soluble vitamins – A, E, K and D – might be observed.
The intention should be to use these medications as part of an overall nutritional plan for weight loss and exercise and he cautioned that using pharmacological agents to achieve weight loss could promote the continuation of deleterious practices such as over feeding and not exercising the animal.
Medications should not be the sole means of trying to achieve weight loss. He emphasised that the products are for use in dogs only and practitioners should resist the temptation to use them in cats.
Mr Chan acknowledged that the use of pharmacological agents to control food intake was “unpalatable” to many vets and pet owners but it is one of the “extreme measures” that should be discussed in order to emphasise how important maintaining a healthy weight is and how far we should go in tackling the problem.
