If the body is an engine, then the food we eat every day - including what is stored inside the liver, muscles and fatty tissues - is the fuel that powers it.
To turn this food into energy, the body relies on a complex system driven by hormones, particularly insulin, which transports glucose from the blood into the cells.
In patients with diabetes, this system goes awry and a poor diet only worsens it, says Dr Lee Chung Horn, an endocrinologist at Gleneagles Medical Centre.
The metabolic disease is on the rise in Singapore. More than 11 per cent of the population have diabetes, up from 9 per cent in 2004.
Type 2 diabetes develops when the body fails to produce enough insulin or is unable to use it properly, while type 1 diabetes arises when the pancreas does not make insulin, a condition that cannot be prevented.
Dr Kevin Tan, vice-president of the Diabetic Society of Singapore, said a person's weight is the "single most contributory environmental factor" in the development of type 2 diabetes and this can be controlled, he said.
Asians whose body mass index (BMI) is 18.5 to 22.9 fall within the healthy range.
Those whose BMI is 23 to 27.4 are overweight, and those whose BMI is 27.5 and beyond are obese.
Dr Daniel Chew, head and senior consultant at the department of endocrinology at Tan Tock Seng Hospital, said that besides diabetes, intentional weight loss can also improve other obesity-related risk factors of coronary artery disease.
These include dyslipidaemia (unhealthy blood cholesterol levels) and hypertension.
EXERCISE IS KEY
Weight loss can be achieved by increasing one's physical activity and reducing one's calorie intake.
Dr Joan Khoo, who heads Changi General Hospital's department of endocrinology, advised people to at least do moderate-intensity activities of 30 to 60 minutes (or divided into sessions of 10 to 15 minutes) a day, for four or five days a week.
The lower the exercise intensity, the longer one will need to do the activity to burn more calories. Also, daily exercise of short durations (30 to 45 minutes) is more effective for weight loss - and less likely to lead to fatigue or injury - than an intense, three-hour gym session just once a week, she added.
Dietitians said in general, people with diabetes should eat healthily by having adequate fibre, choosing low glycaemic index food which does not cause blood sugar levels to spike and reducing the amount of saturated fat, trans fat, cholesterol, sodium and added sugars. These raise a person's risk of cardiovascular diseases.
Ms Ong Fangyi, a senior dietitian at National University Hospital, said patients requiring insulin injections should tailor their meal timings and frequency to their insulin regimen, with the help of a dietitian.
Generally, patients should spread out evenly the total volume of carbohydrates they require in a day, by having a meal or snack every four to five hours while watching their food portions to avoid overeating.
Ms Lynette Goh, a senior dietitian at National Healthcare Group Polyclinics, said a meal should have between 45g and 60g of carbohydrates while a snack should contain about 15g.
A good guide is to have a meal that comprises vegetables that fill half your plate, a palm-sized portion of protein such as chicken without skin or fish, and about a fist-sized portion of rice.
A healthy bedtime snack would be three pieces of wholemeal crackers with a slice of reduced fat cheese or a thin spread of peanut butter. The person can also down a glass of low-fat milk, she added.
BEWARE THAT SWEET TOOTH
Both Ms Ong and Ms Goh advised patients to eat sweet food items only occasionally. The portions of such sweets should be small, and they should substitute for other carbohydrate-containing food in the diet, so as not to raise the total carbohydrate intake in a day.
For instance, replace 1/3 cup of cooked rice or noodles (15g of carbohydrates) with 15g of sweets, which could be two small cookies, 1/2 cup of vanilla ice cream or one fun-sized chocolate bar, said Ms Goh.
placements to help meet their nutritional requirements.
Mr Derrick Ong, a dietitian from Eat Right Nutrition Consultancy, warned diabetics against going on extreme diets that exclude whole food groups, which can increase a person's risk of nutritional deficiencies.
This article was published on May 8 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.