As her knees began to crumble, Sharon Kelly, of Spateston, was so overweight she winced in pain every time the local bus went over a speed bump.

Her joints were struggling to cope with the layers of flesh wrapped around her slender frame but with amazing determination she has turned her life around and is now planning to inspire other slimmers to follow in her dainty footsteps.

The 45-year-old had never thought seriously about losing weight until she was ordered to shed three stone before surgeons would consider operating on her 21-stone body.

Now, one year later, the mum-of-three has dropped an incredible 12 stone after discovering a weight loss programme that worked for her.

Sharon, who works as a practitioner for a children’s charity, said: “I started putting on weight when I was 27. It was during my second marriage and I was really unhappy.

“I began comfort eating to try and cope but never realised just how big I was getting. I’d eat four roast dinners a week as they were cheap and easy to make and I loved the taste of them. For each one I’d have at least 12 roast potatoes and four Yorkshire puddings.

“When I was at uni at an older age, I’d drink up to 12 lattes a day as well, I never even realised how fattening they were.

“It’s horrendous now when I think back to it. I was eating more than 8,000 calories every day. Now I don’t even like the taste of a roast potato.” The incredible slimmer said that the weight began to creep up and, after years of gorging on calorific dinners, she was left with arthritis in both her knees.

“I’d tried everything to lose weight before and it wasn’t until my health went downhill I decided to do something about it,” Sharon said.

“The doctors wouldn’t operate on me unless I lost three stone, but after losing two and a half I was struggling to get the rest off.” After finding information about the benefits of health shakes on Twitter, Sharon tried a final method to help her shed the pounds. By Christmas, she’d lost an applaudable five stone and was down to a size 22 for the first time in years.

“My goal was to get down to a size 18, but when I started losing the weight I never went back to my old diet.

“When I went back to the doctors they were amazed and said I didn’t need surgery any more because of how much weight I’d lost.

“Now they want to use me as an example of the benefits of slimming down before going for an operation.” Now a trim size eight, Sharon’s health problems have practically disappeared and she hopes to be an inspiration to others in future.

As well as launching her own fit camp in the town, she has started up a local walking group, called Johnstone Jaunters.

“I wanted to help other people and start a group in the community where people can exercise but have a chat and a bit of a laugh at the same time,” Sharon continued.

“People walk past me now I’ve lost the weight. I keep forgetting that I must look so different, it’s been amazing.” Her friends and family were so impressed with her progress they have now started the special diet which has also helped her husband Kenny, 48. lose three stone.

Sharon said her children, Robert, 21, Becky, 16, and Melanie, 14, have told her how proud they are of her transformation.

She added: “I feel so much healthier, have more energy and can walk for miles now. Before I couldn’t even walk up the stairs. I would never have in a million years thought I’d be working in the health and fitness industry in future.

“Over a year ago I never cared about how I looked, now I’ve turned my weight loss into my business.”