Elaine Pendlebury, PDSA senior veterinary surgeon, said pet obesity causes "daily misery for millions of pets."
She added, "vet practices across the UK see the consequences of pet obesity every single day such as obese dogs unable to enjoy regular walks due to exhaustion, fat cats that can't jump or play, and rabbits so hopelessly overweight they can't clean themselves properly."
More top news
More than 1.85 million people have called for the US president's visit to be watered down to avoid causing "embarrassment" to the Queen.
Jim Mattis arrived in Baghdad on the day after US-backed Iraqi forces launched an operation to reclaim Mosul from IS.
The scale of the blood poisoning disease sepsis is "far worse" than previously thought thanks to a "crippling" lack of data, a study says.