Technically, obesity is defined as a body weight 20% or more above ideal body weight, however most often categorizing a pet as obese is made based on a subjective evaluation. While the actual weight is important for the purpose of having an objective unit of measurement, I will use observations made on an examination to determine whether or not I believe an animal is significantly above its ideal weight.
The cause(s) of obesity are complex, and involves disorders of energy metabolism, satiety (the feeling of being satisfied after eating) control, as well as genetic and environmental factors. Common causes include overeating (for many reasons), decreased exercise, and genetic influences. In addition, neutering/spaying has been demonstrated to be a risk factor for obesity.
TREATMENT/PREVENTION OF OBESITY:
First, a calculation of your pet’s resting energy requirement can be made. There are additional calculations that may be needed based on an animal’s activity level. This calculation gives us a daily calorie requirement for normal activities. However, it must be stressed that this number is only a starting point and may need to be changed for the individual.
When trying to achieve ideal body condition for the overweight dogs I will usually recommend a high fiber diet (preferably dry), as this has been shown to improve satiety, and thus weight loss, in dogs. In cats, the normal approach is to use a canned food that is higher in protein and fat, and lower in carbohydrate (sugar). Many find that dividing the feedings into multiple meals improves the outcome.
The use of treats is not prohibited, but must be added to the calculation of daily caloric intake. It is therefore recommended to use either pieces of the food from the diet or low-fat treats, such as carrots.
Providing exercise in the form of walks and chasing a ball works well in dogs. In cats (especially indoor cats) providing exercise can be more challenging. We have found that the use of stick and string with a toy at the end for the cat to chase can work in most cases. Another gadget used is a laser pointer. Many cats will chase that red dot around the room for quite a while.
Whatever the plan is, follow up examinations and weight checks are important to determine the efficacy of that approach.