Why would a healthy dog lose weight?

Our question this week was:

Dear Dr. Debra, What causes a dog to loose weight when it is eating healthy, drinking water, urinating and having a good bowl movement?


Anna Simmons


Hi – thanks for your email Anna. You wrote that your dog seems healthy – is eating well, drinking normally and having normal urine and bowel movements but seems to be losing weight. It does worry me.

I'd think about two underlying causes. First, if he is more active and burning more calories – that would be a reason. I recently saw a client that moved from a small apartment to a house with a fenced in yard (6 acres) and her dog lost weight. But he was getting tons of exercise he wasn't used to get, burning more calories and this losing weight.

The other possible cause is some underlying medical problem. Several diseases can create a big burden on the body and burn excessive calories. In those cases, one of the first signs you may see is weight loss.

I'd recommend that you take your dog in to your vet for an examination. Dogs are so good at hiding that they are ill – often by the time they show us additional signs – some conditions can be quite advanced.

Weight loss is not normal in a dog with no change in his diet or activity level.

An article that might be helpful to you is Weight Loss in Dogs.

Best of luck!

Dr. Debra

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