Cocker Spaniel Nyah was nearly 60% heavier than a healthy dog of her type should be, tipping the scales at 4 stone 10lbs (29.8kg).
Now, half way through the PDSA's Pet Fit Club programme, she weighs a much trimmer 3 stone 9lbs (24.95kg), edging closer to her ideal weight of 21kg.
Owner Catherine Jeng, 69, said: "Nyah loves people and other dogs and she's very laid back and very lazy. She was diagnosed with epilepsy at the age of four and is on medication. As a result she's not very active, which probably hasn't helped with her weight problems. But I'm guilty too as I love to spoil her."
"She's got a waist again, which is fantastic. She's become a bit of a diva now!"
Nyah's diet and fitness programme is being specially tailored by the vets and nurses at the PDSA Glasgow PetAid hospital in Shamrock Street.