Is it common for cats to lose weight as they age. Popsie's 16 and I've noticed over the past two years he's been getting skinny. The area it's concentrated in is his hips. His middle section still looks good. His shoulders are also getting some what bony. Popsie was always a lean cat. I would say he never weighed more than 11 pounds. I weighed him tonight and now he's down to seven. He eats very well, no problem with that. Like I said the weight loss has been gradual. Should I have any concerns?