MARILYN Horner isn't the woman she used to be -- and it saved her life.

Her daily diet and fitness regime has knocked seven stone off her 21-stone weight in less than two years.

But her cycling, swimming and healthy eating routine isn't just so that she can get into smaller dresses.

Without it, she probably wouldn't have reached the age of 47.

Marilyn, of Burns Road, Little Hulton, was admitted to hospital just over two years ago to be treated for a chest infection.

After a routine blood test, a doctor arrived by her bed and started talking to her about the insulin she was taking for her diabetes.

She was stunned. Not only was Marilyn not taking insulin -- she hadn't a clue she had been suffering from diabetes for years.

She knew she was always thirsty and pouring herself glasses of squash but she put that down to her big size.

She was also aware she had to go to the loo more often than other women she knew -- but assumed her excess pounds had weakened her bladder.

The doctor explained that her blood sugar levels were so incredibly high that she could have been in a coma in another few days.

"I was shocked," said Marilyn. "The idea that I might be diabetic had never crossed my mind."

Marilyn admits that the news left her "reeling." But it also made her determined to change her life. Her condition is now controlled by tablets -- she is one of the lucky ones who can cope without daily insulin injections -- and she is a dedicated follower of a new lifestyle programme suggested to her by a specialist diabetes nurse.

As well as healthy eating and steering clear of the wrong types of foods, she has learned to swim and also rides a bike. "I feel healthier than I have done in years," Marilyn said.

"I'm only 5ft tall, so when you think about it, I have been carrying a seven stone person around with me all these years.

"Now my confidence has soared, even though I still have to lose another three stone.

"I've just finished a computer course and hope to get a new job."

Marilyn needs only to watch TV or open a daily newspaper to see how people with her condition do not only lead normal lives but incredibly active ones, too.

Olympic rower Steve Redgrave is probably the most famous but in both professional and amateur sport there are many others.

They include former Spurs and England footballer Gary Mabbutt. He continued playing at the highest level despite being diagnosed in 1980.

Although 1.4 million people in the UK are known to have diabetes, experts believe the real number could be more than two million.

Like Marilyn, thousands of people are probably unaware they have it. But, left unchecked, diabetes can lead to blindness, kidney failure and circulatory problems. By the time it is discovered in many people, damage has already been caused.

Amanda Vezey of Diabetes UK (the former British Diabetic Association) says many people do not realise they have diabetes because they are unaware of the symptoms and risk factors.

Doctors told Marilyn that her obesity had probably triggered her diabetes.

Diabetes UK has sent the BEN a fact pack which includes information about the warning signs. WHAT SHOULD YOU LOOK FOR? Increased thirst.

Frequent trips to the toilet -- especially at night.

Extreme tiredness.

Weight loss.

Regular bouts of thrush or genital itching.

Blurred vision. MOST AT RISK ARE: Over 40s -- the older you are the greater the risk.

People with a family history of the disease.

Those who are very overweight.

People from Afro-Caribbean or Asian backgrounds.

Women who have had a baby weighing more than 8lbs 8ozs.

The condition can be triggered by such things as pregnancy, surgery or even the physical or emotional shock of a car accident or bereavement.

Diabetes UK Careline number for further advice is 020 7642 2732. It is open 9am to 5pm weekdays.