Before people develop diabetes, they often already have a condition called prediabetes.
If it is diagnosed, it should not be taken lightly as it is a warning sign that diabetes can develop later unless lifestyle changes are made.
The latest National Health Survey in 2010 found that people with an impaired glucose tolerance (IGT, a common form of prediabetes) comprised 14.4 per cent of adult Singaporeans aged 18 to 69 years, up from 12 per cent in 2004, said Dr Kevin Tan, vice-president of the Diabetic Society of Singapore.
If you have IGT or another form of prediabetes called impaired fasting glucose or both, it means that your blood glucose levels are higher than normal but not high enough to be classified as diabetes.
Prediabetes occurs when your body cannot make enough insulin, or when the cells in your body are becoming resistant to insulin, a hormone that moves glucose from the blood into the cells. Many people with prediabetes develop type 2 diabetes within 10 years.
Prediabetes has no clear symptoms, but there are various risk factors, including obesity.
If you are severely overweight, you may already have prediabetes and not know it.
According to Dr Tan, those who are at risk of developing prediabetes include the obese, those with a family history of type 2 diabetes and those with high blood pressure and high triglyceride levels. Women who have had diabetes during previous pregnancies and who have had large babies, as well as those with an endocrine disorder called polycystic ovarian syndrome, are also at risk.
According to the health survey, women generally have higher rates of prediabetes than men (15 per cent versus 13.5 per cent), for unknown reasons.
The good news is, early treatment helps to prevent or delay the onset of diabetes.
Known as a silent killer for its easy-to-miss symptoms, diabetes can lead to complications such as blindness, leg amputation, kidney failure, heart disease and stroke.
"While debilitating, these complications are highly preventable if diabetes and other risk factors are treated," said Dr Stanley Liew, an endocrinologist at Raffles Hospital.
ABDOMINAL FAT MOST HARMFUL
Studies have shown a close link between body weight and diabetes.
"As a person gains weight, the blood sugar levels rise. The risk of diabetes increases dramatically once the body mass index is above 23," said Dr Liew.
"The most harmful type of fat is the accumulation of fat within the abdomen. An individual of normal weight is still at risk of developing diabetes if he has excessive abdominal fat," he said.
Losing weight through dieting and exercise helps to improve blood sugar and the other parameters of prediabetes.
Doctors said a modest weight loss of even 5 per cent can lower your risk for diabetes, high blood pressure, high blood cholesterol and heart disease.
Dr Alvin Ng, endocrinologist and physician at The Endocrine Clinic, said: "Exercise has been shown to reduce the risk of developing diabetes.
"Combining aerobic and weight training exercises appears to have the greatest effect in reducing the risk of diabetes."
A weight loss of about 0.5kg per week is considered "safe", he added.
HOW TO FIGHT WEIGHT GAIN
That said, it is always easier to prevent yourself from gaining too much weight in the first place than to try to lose it.
Doctors say the key to preventing weight gain is to keep physically active, exercise regularly, watch what you eat and avoid food like sweets.
For those looking to lose weight, Dr Liew suggested the following, using the analogy of accounting in weight management.
"Start by measuring your current weight. A pound of fat equates to about 3,500 calories," he said.
"In order to lose a pound of fat in a week, you have to have a deficit of 500 calories a day. A practical way to create this 500 calories deficit is by eating 300 calories less and exercising 200 calories more a day."
For example, you can achieve this by forgoing two cans of soft drinks and walking an extra 4,000 steps per day, he added.
Physical activity should also be incorporated into your lifestyle.
Dr Ng said that even if you do not lose weight, regular moderate physical activity, including brisk walking, can reduce the risk of developing diabetes by about 30 per cent.
This article was published on April 24 in Mind Your Body, The Straits Times.Get a copy of Mind Your Body, The Straits Times or go to straitstimes.com for more stories.