It may have been Bugs Bunny's favourite treat but an animal charity has warned that too many carrots are making the nation's pet rabbits fat. The PDSA has said that obesity levels in pets is at an all-time high, with experts predicting that more than half will be classed as overweight within five years. Around one in three dogs and one in four cats are already said to be overweight. Too many treats, the wrong type of food and lack of exercise were to blame for turning some of the nation's bunnies into giants,  the charity added. Scroll down for video . Grace the giant overweight rabbit has joined the PDSA's annual Pet Fit Club competition for overweight animals . Carrots were named as the worst culprit as the vegetables are very high in sugar and so should only ever be given as the occasional treat, not as regular feed. Nicola Martin, PDSA Head of Pet Health and Welfare, said: 'Sadly, many of our 1.3 million pet rabbit population in the UK are 'unhappy bunnies', as many of their welfare needs are being neglected. 'The good news however is that pet obesity is entirely preventable. Experts have warned that more than half of pets will be overweight in five years with carots named as the worst culprits for bunny obesity . Now in its tenth year, the Pet Fit Club puts pets on a six-month diet and exercise programme overseen by vets, leading to one being crowned a super slimmer . 'So we're advising owners that, while feeding their pet a treat may be rewarding in the short term, as a way of showing affection, the long term impact is serious. They could be killing them with kindness.' PDSA research revealed that four-out-of-five veterinary professionals had seen an increase in pet obesity cases in the last two years. The problem of fat pets has become some widespread that the runs an annual Pet Fit Club competition to put them through their paces. Porky pets are placed on a six-month diet and exercise programme overseen by vets, leading to one being crowned a super slimmer. A veterinary nurse holds bulldog Daisy from Middlesbrough, who weighs 28kg - she is one of 17 of the UK's podgiest pets, who are competing in an annual competition known as Pet Fit Club . Andy Cage from PetAID hospital says that obesity is one of the biggest animal welfare problems . Last year's candidates included Daisy the obese bulldog from Middlesbrough, who at 4st 6lb, was double the weight she should have been. Fellow rabbit Poppy was a third heavier than she should be at more than 7lb – mainly due to a taste for popcorn. Owner Donna Manson said that her rabbits are not dissimilar to us, piling on the pounds over winter, the peak time for comfort eating. Zorro, a three-year-old ginger Tom from Dundee, became so fat he could no longer groom himself and would often wake owner Linda Petrie in the middle of the night for his favourite snack: cheese and onion crisps. Donna said that she had no idea that some of the treats she was giving to her bunnies were so fattening. A happy bunny: Poppy the rabbit was one of last year's competitors in the PDSA pet fit club who has slimmed down now (right) forweighed 7lbs (left) when she entered . Ginger Tom Zorro has become so overweight he is unable to groom himself . 'I've tried to cut down on the carrots and apples, as I've recently learned that they are both high in sugar and not the healthy snacks I thought they were,' she added. Other candidates included a cat that can open the fridge and a Jack Russell with a taste for doner kebabs. PDSA Pet Fit Club was launched in 2005 and has already helped 57 dogs, 24 cats and 3 rabbits lose a total of 295kg (46 stone 6lb). This weight loss is the equivalent of nearly 300 bags of sugar, more than 4,400 sausages, 740 tins of dog food or over 1,000 blocks of lard. Senior Veterinary Surgeon, Andy Cage, from Dundee PetAid hospital, said that having over weight animals is not just a nuisance, it is also an issue of cruelty. 'Obesity is one of the biggest welfare issues affecting pets in the UK today. Sadly, it also means millions of pets are at risk from potentially life-threatening health problems related to obesity. 'But the good news is that obesity is entirely reversible.'
Too many carrots are making the nation's spoilt pet rabbits overweight.
PDSA has warned that more than half of pets will be obese in five years.
Charity's Pet Fit Club returns for a tenth year to help slim down porky pets.
It has helped animals allover the UK lose the combined weight of 46 stone.