It's not just humans who need to watch their weight - just take a look at George the cat.
Eight-year-old George was a normal size when his owner Emma got him three years ago. Since then, he's ballooned to 8kg - twice the size of a regular moggy.
Vets say overweight pets can get lots of health problems, so Emma and her family are doing things differently.
They've changed his diet, got him exercising more and they take him to the vet for a check-up every two weeks.
George's vet from the pet charity PDSA said: "We are seeing more and more overweight pets.
"Owners will bring in animals for a health condition and the animal is overweight. That can be the cause of the health condition."
George is already seeing the benefits of his health kick - he's lost half a kilo and is looking at a brighter future.