The glycemic index (GI) and glycemic load (GL) are tools used to help inform people with diabetes what foods they should be choosing, to help keep their blood glucose levels in check.
The glycemic index measures how fast your blood sugar levels rise after eating particular types of food. Some low GI foods cause your blood sugar level to rise slowly, while others – high and medium GI foods – cause them to rise more rapidly.
However, this measurement does not take into account the portion sizing of the food, or total sugar ‘load’. This is where the glycemic load table comes into play. The glycemic load is used to give a more practical indication of the affect the foods, in given quantities, will have on your blood sugar levels.
.
Glycemic Index
The glycemic index, or GI, is a helpful tool to guide you in making the most informed choices of foods containing carbohydrates. When carbohydrates break down in the body they are turned into glucose which your body uses for energy.
The glycemic index is measured on a scale of 0-100. Pure glucose is the highest with the number of 100. The foods are determined on 3 different levels:
- Low GI: GI less than 55
- Medium GI: GI between 55 – 70
- High GI: GI over 70
Low GI foods are the best foods to choose. However, if you choose to eat a high GI food, it is best balanced out by also consuming a low GI food. This will result in a milder rise in levels.
Some examples of where foods sit on this scale include:
- Low GI: Traditional or steel cut oats, most fruits, beans and lentils.
- Medium GI: Couscous, basmati rice, wholegrain bread.
- High GI: Wraps, melons, short grain rice.
Glycemic Load
The glycemic load, GL for short, is calculated by taking the number of grams of carbohydrates per serving, multiplying it by the GI number and then dividing it by 100. These figures are then rounded to the nearest number.
The aim is to keep the total GL number of the day under 100. Some examples of this table are:
- The GI of a carrot is 47 with approximately 5g of carbohydrates –
Therefore: GL= 47 x 5/100 = 2.35 (2) - The GI of white bread is 70 with approximately 14g of carbohydrates –
Therefore: GL = 70 x 14/100 = 9.8 (10) - The GI of oatmeal is 58 with approximately 21g of carbohydrates – Therefore: GL = 58 x 21/100 = 12.18 (12)
Due to the fact that the glycemic load looks at both components of a food, (that is, Glycemic Index and volume) a food with a high GI and a low GL may be better for you than expected. Assessing both components of a food may give you a better range in what you can safely eat.
Eating both low GI and low GL foods together will help you to feel fuller for longer helping you to eat less. Combining the two dietary tools will help with the management of diabetes, as well as prevent further diseases, complications and even obesity in the future.
Be sure to combine them with regular physical activity for the best results in controlling blood sugar levels.
