Increase in appetite

[BrandNewShinyThings]

My 6 yr old rescue cat has suddenly developed an increase in appetite, over the last week or so. He's booked in to see the vet on Monday but in the meantime I would appreciate any thoughts or advice.
He has always had one sachet of Felix AGAIL in the morning, half a sachet for tea and a handful of biscuits in the evening. His weight has been stable for the 4 years we've had him following this diet. He is now wolfing down his breakfast and then seems desperate for more mid morning, if I put another sachet down he will wolf down all of that and then sleep for the rest of the day.
He was wormed at his 6 monthly check up in March before lockdown, where he was found to be in good health. I'm so worried he has a serious condition, he's such a gentle boy and very much loved.

It could be thyroid, although he's a bit young to develop that, but it's still a possibility. If it is that then it's reasonably easily treated - a few weeks on tablets to stabilise levels then a thyroidectomy.

Thanks so much for your reply and good to know its easily treated. Googling also brings up diabetes? I am hoping the vets will do blood tests.

That happened to my old fella and he has been diagnosed with overactive thyroid.

Is yours losing weight, despite eating more and breathing fast?

@Zisforstripyoss

That happened to my old fella and he has been diagnosed with overactive thyroid.

Is yours losing weight, despite eating more and breathing fast?

He does look a bit thinner to me but its hard to tell by looking, did they manage to treat your cat? Hope he's OK.

If you haven't noticed increased thirst then it's less likely to be diabetes.

@thecatneuterer

If you haven't noticed increased thirst then it's less likely to be diabetes.

Thanks that's very reassuring, no increase in thirst. Will see what the vet says tomorrow. Going to be hard handing him over, he's not a very brave boy, I wish I could go in with him.

Did you go to the vets yet op?
Our cat is only 7 months old, and was spayed a few weeks ago, since then she is eating like a horse. She has two sachets plus biscuits but is always after more, today because she was shouting at me everytime I went in the kitchen I gave her another sachet so that's three today! She's not fat at all but has grown lately. Up to date with flea and worm treatment. Is she just greedy or having a growth spurt?