I have a 12-year old cat called Jarvis. That's him in the picture, with the one ear. He's always been a bit on the large side, so when he went for his annual vaccinations last week, it was a bit of a shock to be told by the vet that he is 'clinically obese' and needs to go on a diet.

His current weight is 6.4 kilos, and he should be around 5 kilos. To put this in context, it's equivalent to me trying to go from 12 stone to 10 stone!

Feline obesity is a growing problem and it can lead to serious health problems such as diabetes, liver disease, arthritis, heart disease, respiratory problems and lower urinary tract problems.

To help Jarvis lose weight safely, the vet has supplied me with some special "obesity management" cat food. He is restricted to just two 25g portions per day. Luckily, Jarvis likes his new food, but he misses his tinned food and stares at his food bowl longingly, as if to say "is that all there is?"

The special food should allow him to safely lose between 1 – 2% of his body weight per week, so he should reach his ideal weight in about 12 – 20 weeks. However, he needs to go for regular weigh-ins at the vets every two weeks to make sure he's not losing weight too quickly. So he's now an official member of the "fat cat" club!