More and more people are now trying new diets and struggling to lose weight, usually because they have followed the conventional advice of low calorie and low fat.

Overweight people lost more weight on low GL (glycaemic load) diets than on high GL or other weight reduction diets and their cardiovascular risk marker profile improved according to a review in July 2007 carried out by the highly respected and independent Cochrane Collaboration.

The Glycaemic Index tells us how quickly the sugar in the food raises the sugar in our blood, Glycaemic Load tells us just how much of that sugar is in the food we are eating making the GL measurement of food a more balanced indicator than just using GI. Eg. the GI of Mars bars is around 68 and is the same if you eat 1 or 21 Mars bars, the GI of watermelon is 72 as it contains fast releasing sugars but very little of them. GL would then take the weight of these sugars in the food consumed into the equasion and is more realistic. By using the GI and multiplying by the quantity of sugar in a serving (GI (%) x grams of carbohydrate per serving) we get the total glycemic response to a food or meal which is a very good indicator of the overall affect on our bodies.

The glycaemic load test is ideal for those people starting a low GL diet or with a family history of diabetes

The glycaemic (blood sugar) response to carbohydrate foods is less pronounced when carbohydrate foods are eaten with proteins and/or with fats; this is usually the case with most snacks and meals. The glycaemic response from a cheese sandwich is slower and lower than the glycaemic response to eating the same amount of bread only; the glycaemic response from eating a baked potato is slower when it is eaten together with baked beans. The other factor that needs to be considered is the amount of carbohydrate in a typical portion of food consumed. The Glycaemic Load (GL) is a measure of the total glycaemic response to a food or meal calculated with the GI figure and the amount of carbohydrate in a serving. In practice, the GL is a marker for the blood glucose effects of foods/meals consumed. The small amount of carbohydrate in a typical portion in some high GI foods, such a carrots or watermelon, gives them a low GL figure.

The GI and GL concept are useful for people with diabetes, who need to balance their blood glucose levels with medication. The concept has also been used to plan the diets of sportspeople, to match the supply and demands for glucose in relation to training and performance. Some studies have suggested that diets with overall lower GI levels may reduce the risk of metabolic syndrome and coronary heart disease, and may support the prevention and treatment of obesity. Many dietitians are involved in further research to clarify the best application of GI concepts in dietary advice, to prevent disease and support good health in the population.