Don't look!

Perfectly healthy looking rat. Except that it is dead of course. 

This is not the fattest rat I have ever seen, I saw a rat on Calton Hill so fat his tummy dragged on the ground and he had to paddle his little paws from side to side to run away. 

This is not the biggest rat I have ever seen, I saw a rat in London Road Gardens eating sunflower seeds put out for the squirrels. He was big and sleek and confident enough to walk through the railings and sit with his tail curled round his paws waiting for me to go away so he could go back to eating sunflower seeds. He didn't even hide. 

Don't put cooked food in your compost, bin it properly. Don't put seed out for the birds unless it is high up. Rats really are vermin.