Diets low in GI have been endorsed by the World Health Organisation (WHO) as helping to beat ‘lifestyle diseases’ of the developed world. So what are you waiting for?
The glycemic index or GI is a ranking of carbohydrates according to their effect on raising blood sugar levels after eating. On a scale from 0 to 100, foods with a high-GI are those which are rapidly digested and absorbed, leading to marked fluctuations in blood sugar levels. Low-GI foods, digested and absorbed more slowly, result in gradual rises in blood sugar and insulin levels.
The benefits of a low-GI diet include better weight control, reduced cholesterol, prolonged physical endurance, improved glucose and lipid levels in people with both types of diabetes and reduced insulin levels and insulin resistance. WHO’s endorsement of low-GI diets is due to their proven long-term prevention of the most common diseases of affluence, such as coronary heart disease, diabetes and obesity.
Low-GI carbohydrates slowly release glucose into your blood stream, keeping energy levels balanced and ensuring that you feel fuller for longer. As such, it is a sustainable – and healthy – way to reduce excess body weight.
GI ratings are determined by measuring blood sugar responses in healthy people fed measured portions of carbohydrate after an overnight fast. Finger-prick blood samples are taken at 15-30 minute intervals over a two hour period with the GI rating being the average between all subjects’ ratings.
Diseases of affluence
Eating lots of foods high in GI pushes your body to extremes which can be detrimental to your health, particularly if you are overweight and don’t exercise regularly.
According to the Australian Bureau of Statistics, in 2004-05, 53 per cent of all adults were either overweight or obese, an increase from 44 per cent in 1995. Overweight and obesity have reached epidemic proportions worldwide and increase a person’s risk of chronic illnesses including diabetes, cardiovascular disease and some cancers.
The risk of developing type 2 diabetes is strongly related to the GI of one’s overall diet according to recent studies from Harvard School of Public Health. In 2004–05, 3.6 per cent of the population reported they had diabetes, according to the Australian Bureau of Statistics, substantially higher than 2.4 per cent of 1995.
People with diabetes aged 45 years and over are 2.3 times more likely to have glaucoma, 2.2 times more likely to have a heart, stroke or vascular condition, and 1.9 times more likely to have hypertension. Also on the rise is gestational diabetes, experienced by about 3–8 per cent of pregnant women, which increases one’s risk of developing type 2 diabetes.
Switching to a low-GI diet
The good news is that it’s becoming easier to choose foods low in GI. The Australian Food Industry is responding to calls from health and advocacy groups for greater information on GI and many Australian-marketed foods already show their GI rating on the nutrition information panel.
Factors influencing GI rating include: the type of starch and its ease of digestion; the cooking time, which swells starch and increases the GI rating; processing of foods as highly processed foods tend to have a higher GI rating due to the speed of their digestion; fat content, which changes the way the body digests, foods with higher fat content tend to have lower GI ratings; acid content which slows down digestion.
A low GI rating is 0-60; intermediate GI is 60-70; high GI foods are 70-100. It’s easy to go low, you just need to remember some simple guidelines – highly-processed, easily-digested foods have a higher GI rating while more natural, harder-to-digest foods tend to have a lower GI rating. Plan meals around low GI foods such as lentils, barley and couscous and feel full for longer.
Swap this for that
Swap wheat-based cereals for oats, barley and bran cereals
Swap jasmine or ‘instant’ rice for basmati or doongara rice
Swap bread for pasta
Low-GI foods include:
- Wild rice
- Brown rice
- Wholemeal pasta
- Kidney beans
- Soya beans
Avoid or minimise
Pastries and cakes using white flour