-Lack of exercise
-Neutering / spaying
-Phenobarbital (anticonvulsant) can decrease satiety leading to overeating Glucocorticoids can lead to abnormal fat deposition and weight gain.
-Genetics - some breeds are just more prone to putting on weight than others
A decrease in calorific intake and increase in exercise is the healthy way towards weight loss. High-protein, low-fat foods produce optimal weight loss as protein and fibre stimulate metabolism and increase satiety. Eliminating table scraps and treats is imperative. Feeding low-calorie treat / green beans and other vegetables is a good alternative to regular treats. Use slow feeders to feed them to lengthen meal times and reduce portions. Replace kibble with fresh food as kibble contains a large amount of carbs.