Cat has recently started to smell

Question
My cat has recently started to smell bad and I'm quite worried about her. She's around 16/17 years old, and for the last month or so there has definitely been a bad smell coming from her. She has also lost a fair amount of weight. She has always been slightly over weight and despite years of trying to help her lose it, she has suddenly become the size of a normal cat in a fairly short period of time. She seems happy and content, and is still capable of cleaning herself so it isn't that, but was just wondering if there might be an underlying medical condition

Answer
HI Alice,
Sorry to hear about your kitty's problem.  Because I suspect that, at her age, this will most likely be something medical, this
really goes out of my field of expertise.  I would take her to your vet as soon as you can to find out what is going on with her.
Thank you for using All Experts and I am sorry I could not be of more assistance.
Thank you again, and best of luck with your longtime companion.