Underweight Cat

We have a cat who is currently underweight and are wondering if there is more we can be doing to ensure he maintains and hopefully gains some weight? I'll post his history as his cirumstances may explain some things.

We have had our cat Max for about 11 years. We're not sure how old he is because he was a stray living near our house that we eventually took in. Vet at that time esitimated he was about 2-3 years old. When we took Max in he was very thin, about 4.5 lbs, though after proper eating and deworming he eventually reached 8 lbs.

He maintained this weight right up until late last year when he was diagnosed with hyperthyroidism. Max's weight loss was very gradual and when he started having trouble eating the vet found him to be about 5 lbs.

Since his diagnosis Max's thyroid levels have been normalized and kept under control with proper medication. He also gained a pound of lost weight back and he is holding steady at 6 lbs. He also eats very well. He is fed wet food twice a day and has dry food accessible all times. However, we keep getting comments about how thin Max is (though the vet is okay with his weight) and we're wondering if there is anyway to promote a bit of weight gain? Max, despite his old age, is also a very active cat.

My Aunt has a hyperthyroid cat as well who is 19 and VERY, VERY skinny. If people didn't know, they'd think he was starving. He is regularly at the vet and inspite of some other issues, is getting on very well actually. He's very well cared for but others would never guess. Don't worry too much about people and their comments, so long as your vet is comfortable with his size and you are doing what you can for him that's what is important. If he started out at 5 or so lbs and his max weight was 8 lbs, 6 lbs being HT isn't that bad, really...he's obviously a small boy.

What are you feeding? Maybe switching to something with higher calories could help, but at his age you want to be careful of kidneys, etc and TOO much protein may not be best either. Though I've heard mixed reviews on that as well.

If he's happy and otherwise healthy, you may be doing the right things already!

If he will eat it, I'd give him a 3rd meal (canned) to help him gain some weight - even if its a small can of kitten food (higher calories).