Glycaemic Index - key to nutrition

by Manjula Fernando

We should really eat five servings of fruit and vegetables per day (400-500g) per day. One serving is equivalent to one orange, mango, banana, apple or one inch thick piece of papaya, half inch thick slice of pineapple three tablespoons of cooked vegetables (1/2 cup) or one cup of raw salad (200 ml) and this is the Magic answer to good health and well-being. But in sharp contrast a Sri Lankan adult only consumes an average of two fruits and just two vegetable servings per day.

Health is wealth, what is perceived healthy today may not be so according to findings that emerge in new research. The Health Education Bureau, the Health and Nutrition Ministry and UNICEF organised a media workshop to mark Nutrition month in June, where many new concepts with regard to eating healthy and staying healthy were shared.

It is accepted that that as you age total food intake needs to be reduced since the metabolism of the body slows down.

Thus exercise is an important component to balancing food intake and output, besides sedentary lifestyle makes exercise even more important.

The elderly are expected to eat high nutritional value food. Although the energy requirement can decline with age if they are physically inactive, the need for proteins, vitamins and minerals are the same for the elderly.

Thus the recommended food are those rich in nutrients and low in calories.

Doctors say infant and early childhood nutritional requirement is high due to rapid growth. In the case of children and adolescents, the nutritional requirement is high, after adolescence (10-19), the growth rate slows reducing the nutritional requirement. Excess nutritional intake without much utilisation makes a person obese.

It has been found that a major cause for childhood obesity is excessive sugar consumption. Would you believe that 4-5 biscuits could give a child 275 Kilo calories.

A child has to walk one hour, to burn 275 kcalories.

After the age of one, a child's growth rate slows and with it the appetite. However, children develop tastes for certain food at an early age and eating habits and attitudes children learn are likely to last a lifetime. It is important to start healthy eating habits (less salt and less sugar) early in life.

The easiest way to find nutritious food is to go by the Glycaemic Index (GI) and Glycaemic Load which offer information about how food affects blood sugar and insulin.

The lower the GI or Glycaemic Load, the less it affects blood sugar and insulin levels. Recent studies from the Harvard School of Public Health indicate that the risks of diseases such as Type 2 diabetes and coronary heart disease are strongly related to the GI of the overall diet.

GI is a ranking of carbohydrates on a scale from 0 to 100 according to the extent to which they raise blood sugar levels after eating.

Food with a high GI gets rapidly digested and absorbed. It results in marked fluctuations in blood sugar levels. Low-GI foods, are slow to digest and gets absorbed gradually. So, there is only a gradual rise in blood sugar and insulin levels. They have proven benefits for health. According to the University of Sydney, low GI diets have been shown to improve both glucose and lipid levels in people with diabetes (type 1 and type 2). They have benefits of weight control because they help control appetite and delay hunger. Low GI diets also reduce insulin levels and insulin resistance.Low GI is below 55 and High GI is over 60.