Glycaemic index (GI) recently evolved into Glycaemic Load (GL), which is now considered to be the holy grail of nutritional interventions for many 21st century diseases.
GI became a popular choice amongst health practitioners and many individuals wishing to improve their health, particularly within the area of weight loss and weight management. GI has been quite succinctly defined as “a measure of blood glucose excursion per unit of carbohydrate”. The GI ranking scale of specific foods run from 0 to 100 with high GI foods scoring above 70, moderate 55-69 and low GI is considered below 55. The functional characteristic of the GI concept is solely limited to an evaluation of a food’s ‘quality’ and resulting speed of blood glucose response.
In 1997 the GI concept underwent a welcomed transformation to evolve into the more balanced and applicable approach of the GL system. GL offers a far more comprehensive approach by way of its equally ‘qualitative’ and ‘quantitative’ evaluation method. The GL value of a food itself is calculated by multiplying the carbohydrate content in grams by the GI value and then dividing by 100. The following are the core GL nutritional principles to follow: -
- Graze – 3 main meals and 2 snacks daily
- Combine protein with carbohydrate at every meal and snack
- Apply portion control and suitable plate proportion guidelines e.g. 25% protein, 25% low GL carbohydrate and 50% vegetables
- Lean meat, fish, beans and pulses as protein sources
- Unrefined and unprocessed low GL carbohydrate sources
- Avoid/limit sugar, alcohol, caffeinated drinks, saturated and trans fats
- Include essential fatty acid food sources
A 2007 Cochrane Systematic Review assessing the effectiveness of low GI or GL diets for weight loss amongst overweight or obese individuals concluded that “lowering the glycaemic index of foods in the diet appears to be an effective method of losing weight, particularly for the obese”.
Specifically, the effectiveness of the low GI/GL diet in comparison to conventional restricted energy low-fat diets was positively observed in the result markers of body mass, total fat mass, BMI, total cholesterol and LDL cholesterol. Other significant observations noted were that the GI/GL diet was simple to follow, enhanced satiety and being generally less restrictive may enhance the quality of life of the individual concerned. This is quite a seal of approval from a Cochrane Database Systematic Review.
The effectiveness of dietary protocols for long-term weight loss and weight management can be evaluated in terms of those associated factors most likely to incur adherence and long-term success, such as satiety, appetite regulation and being socially realistic. The GL approach appears to satisfy each of these considerations effectively, which is perhaps particularly significant in comparison to the conventional weight loss wisdom of low-fat, calorie-controlled abstinence.
GI and GL may be considered as the most honest measures of a food’s functional effects on the body and honouring these will reap substantial health benefits, improve individual quality of life and reduce the economical cost implications of chronic disease management overall. Ditching the flawed low-fat, low-calorie dietary principles and waking up to the GL revolution may be one of the best health decisions you ever make.