A woman branded morbidly obese by her GP has lost 21 stone in weight after an embarrassing trip to the dentists forced her to act.

Denise Petty has gone from a size 34 to a size 14 dress after four years of shedding the pounds.

She has lost so much weight, doctors told her last year a gastric band she had fitted was no longer working and she had been keeping the weight off herself.

Struggling with her weight: Denise Petty, 42, weighed 36 stone in 2009 and could not go upstairs without struggling for breath

Miss Petty said: ‘It was just so embarrassing. I went to the dentists and they could not get the chair to lift me up.

‘I knew then that if I didn’t do something about my weight I would be lucky to survive to the end of the year.’

At the time in 2009, she weighed 36 stone and could not get up the stairs in her house without struggling for breath.

She said she was depressed after years of weight gain and never allowed anyone to take photographs of her.

‘The weight creeps up on you, year after year,’ said Miss Petty.

When she plucked up the courage to go to her GP, he warned her she was morbidly obese but it took the shock of what happened at the dentists to force a change of lifestyle.

She said: ‘I couldn’t walk more than 20 yards. I avoided the GP because he always said the same thing, that I was morbidly obese, and you don’t want to listen, you don’t want to hear it.

‘But it changed my mind and I knew I had to lose weight.’

The 42-year-old health care assistant was referred by her GP to her local Weight Watchers group in Bloxwich, where she said she learned to ‘re-educate’ herself about food and change her lifestyle.

‘It’s about smaller portion sizes and about moderating what you eat,’ she said.

‘It does get harder to lose the weight and to keep the weight off – the temptations never go away.

‘But when I go to my group, I can talk to the others, we can have a giggle and people understand your issues, which has been a great help to me.’

With the support of her family, she also took the step of having gastric band surgery at the Birmingham Heartlands hospital.

‘We thought long and hard about the risks because there was a chance I might die while in surgery, but I felt that if I didn’t do something I would be dead anyway,’ Miss Petty added.

Two years later, her weight loss regime had been so successful she was told her gastric band had ‘stopped working’ some months before and that she had been losing the weight by herself.

Now, she can walk her dog without fighting for breath and is taking her driving test next month.

She is also thinking about getting on an aeroplane to take a holiday abroad.

‘I never wanted to face the embarrassment of thinking I wouldn’t fit in one of the plane’s seats and now I just don’t have that worry,’ she said.

Success: After joining her local Weight Watchers group, Denise Petty cut down her portion sizes and said she had to ‘re-educate’ herself about food

Miss Petty added: ‘I found some of my clothes from before and could not imagine me filling them – they used to be quite tight on me. That is a great feeling to have.’

Having reduced her body weight by more than half, Miss Petty now wants to lose another 10 lbs so she can qualify for surgery to remove the excess skin her slimming has left behind.

Beverley Longsden, Weight Watchers group leader, said Miss Petty was ‘amazing’.

‘I’ve never had anybody who has lost that much weight,’ she said.

‘She knew she had got to lose the weight and she also realised she could not do it alone.

‘She has come each week for four years and that takes a lot because if you have a love of food it never goes away.

‘It will always be an obstacle, trying to take you back to where you were. Weight Watchers is a tool to keep that under control.’

She added: ‘What you don’t realise is people just see your size and until you lose the weight they never see the person you really are.

‘So I am so glad for Denise because she is such a witty, funny, wonderful person.’

Read more: Daily Mail