I have two cats at opposite ends of the weight spectrum. Mac tips the scales at maybe, 6 or 7 lbs. at the most. He has started putting on weight because I started feeding my cats grain-free food. Mac no longer throws up, so he is starting to put on weight at last. Ming tips the scales at 20 lbs., he's my Big Boy. I've had him to the vet and he checks out perfectly healthy, but I am waiting for the new food to take weight off of this cat. So far, no luck. One needs to free feed because he will go down to 5lbs. if I don't. The other needs to loose weight, so I shouldn't free feed him. I'm stuck. The vet says Ming hasn't gained any weight in the last two years, and he passes his checkups with flying colors, so I guess I will stay the course and love him as he is. Still, when Ming was 17 months, I think he only weighed about 14 lbs. If your vet says not to worry, I wouldn't.