Feeding your pet: Which human foods make them overweight?

Animal lovers are being warned that plying their pets with human food is causing them to balloon in weight.

Experts say owners are often unaware how many calories they allow their pets to digest by giving them the "leftovers" after dinner.

The warning comes after an obese Cavalier King Charles Spaniel was crowned 'slimmer of the year' following months of gorging on Sunday roasts that left the normally slight-framed pooch weighing 3st 6lb.

Vets are now urging owners to avoid being too generous with tinned tuna, toast, slices of cheese and crisps - all of which help pets rapidly pile on the pounds.

New figures suggest:

• A single packet of crisps is equivalent to two big steak pies for a dog

• A slice of toast equates to a bag of chips

• Three pieces of cheese are equivalent to two whole cheese burgers

• Feeding your cat a tin of tuna is the same as 35 chicken nuggets

Slimmer of the year Oscar, 10, rocketed to over 80% his ideal weight after months of his owner cooking Sunday roasts - specifically for the dog.

PDSA vet Paul Manktelow warned that over-feeding and leftovers were the "downfall" for pets and their owners, and often the reason behind weight increases.

However, he stressed that regular exercise is just as important for pets.

"We don't think of those things as having that much impact, but they do", he said.

"Cats are very, very small animals, so that's [a whole tin of tuna] quite a big amount of tuna and calories for them".

He added that having the "will-power" and sticking to a regime with your pet is equally important in order to keep them in healthy condition.