The low-fat and low-calorie diets do not stop obesity epidemic in countries like Britain and United States despite the fact that the average number of calories and percentage of calories from fat went down. To the contrary, the obesity epidemic has in fact accelerated. Obesity will cause us gets higher risk of developing into many medical health issues including heart disease.

Dr Atkins realized that it was the carbohydrate that increases the blood sugar and hence the weight. In order to prevent the body from converting carbs into fat, a high-protein, high-fat and low-carb diet was proposed. It works but it does not really make one healthier.

In 1980s, people started measuring GI (glycemic index) of foods, which is a measure of how fast the sugar in food increases one's blood sugar level compared with glucose. GI diet suggests limiting high-GI foods but does not restrict the quantity of carbohydrates.

GL means the quantity of carbs (the Atkins factor) multiplied by the quality (the GI factor). For instance, watermelon has fast-releasing sugar (GI of 72), but a large slice has only 6g of carbs. So multiplying the quantity (6g) by the quality (0.72) gives 4.3 GLs.

The GL value of food tells us more things: what that food will do to our blood sugar level and hence, our appetite, energy and weight.

Low GL diet can be achieved either by eating a low-carb, high-protein diet (and Atkins) or with a higher carb, but strictly low GI carbs and moderate protein diet. Patrick Holford, founder of the Institute of Optimum Nutrition in London, prefers the latter approach. What he suggests is a meal of 45 GLs a day, spaced out in 3 meals and 2 snacks, combining protein with carbohydrate will even out blood sugar and maximize weight loss.

In clinical trials, Atkins and South Beach diets give a weight loss of about 500g a week while the above-mentioned low-GL diet causes a weight loss of 590g a week with 94 percent of participants claiming better energy. The findings were published in the Journal of Orthomolecular Medicine.

A paper published by the American Medical Association also suggested that dietary glycemic load (GL) and not just overall energy intake (calories), influences weight loss.

Moderate reduction in GL appears to increase the rate of body fat loss, particularly for women. Diets based on low-GI wholegrain products maximize cardiovascular risk reduction, particularly if protein intake is high.

Will GL diet become the future of safe, effective and life-long weight control, as what Holford suggests? Perhaps it is too early to tell. Let us wait and see if more favorable clinical findings will emerge to make this come true.