Low-GI and Low-GL

The glycaemic index (GI) was developed to measure the speed at which carbohydrate containing foods are broken down into glucose and absorbed into the blood stream.
Our bodies convert carbohydrates (sugars and starches) into glucose to be absorbed into the bloodstream to be used for energy. This raises our blood glucose levels (also referred to as blood sugar levels).

Foods with a Low-GI (under 55 – e.g. an apple) break down slowly, giving a slow rise in blood sugar and insulin levels. Foods with a High-GI (over 70 – e.g. white bread) break down much faster, sending blood sugar and insulin levels surging high.

Foods that are broken down slowly into sugars for gradual release into the bloodstream will keep the level of your blood sugar (and therefore your energy levels) fairly constant. As a result you are less likely to feel hungry and tired.

Foods with a High-GI are broken down and absorbed very rapidly, giving you a quick burst of energy followed by a slump, leaving you feeling tired, drained and hungry. Because the rapid rise in the level of glucose in the blood is followed by an equally rapid fall, this sends a signal to your body telling it to boost the glucose level again. Eating a chocolate when you are hungry might make you feel better briefly, but the energy boost is short term, as the vicious cycle starts again.

HOW DOES

Carbohydrate containing foods with a Low-GI have the ability to improve the control of appetite, hunger, blood glucose levels and insulin levels in comparison to High-GI foods. Although at times we do need some High-GI and some intermediate GI foods in our diets, it’s important to keep the correct balance, as eating too many foods that have a High-GI value may lead to an increase in body fat.

This is because High-GI foods are broken down quickly to form glucose – this glucose is released very quickly into the blood stream. Insulin then moves these glucose molecules into the cells. Because there is too much glucose available to the body at that time, the excess glucose is converted by insulin into fat and stored in the body in the form of fat.

Because Low-GI foods are broken down slowly into glucose, they are released slowly into the blood stream. This slow release of glucose over a longer period of time will allow the body to use all of the glucose, leaving none to be stored as fat. This also allows the body to use excess body fat effectively as a source of energy.

So if you want to reduce excess body fat, it makes sense to follow an eating plan that is based largely on Low-GI foods. Portion sizes are also important in a healthy eating weight loss programme.

THE GLYCAEMIC LOAD (GL):

The Glycaemic Load refers to the quantities of the carbohydrate rich food you eat.

COMPARING HIGH-GI BREAD TO LOW-GI BREAD

White Bread
(High-GI)

Imagine eating a slice of ordinary white bread (High-GI). Because it is refined and contains very little fibre, it will be digested very quickly. This will give you a quick boost of energy, but because all the energy is released at once, you may feel hungry and tired fairly soon after your meal. This is especially common after lunch and explains the typical mid-afternoon slump.

Some High-GI foods:

White bread, Potatoes, Puffed cereal,
Watermelon, Litchi juice

View the GI Food chart

Seed bread
(Low-GI)

Eating a slice of seed bread (Low-GI) will take a lot longer to eat and digest as it is high in fibre. This will give you the same amount of energy as the white bread, but the energy will last for a longer period of time and keep your energy levels constant. This sustained energy will help you through the day and prevent the mid-afternoon slump.

Some Low-GI foods:

Seed bread, Durum wheat pasta, Rice (Brown or White), Apples, Banana, Low-fat and Fat-free Milk

View the GI Food chart

LOWER THE TOTAL GI OF A MEAL:

Foods that are good sources of carbohydrates and that have High-GI should be eaten occasionally in small quantities. They can be mixed with lower GI foods to make up a balanced meal.

An example: Instead of having a large plate filled to the brim with pasta and a creamy white wine sauce, use less pasta (use durum wheat pasta), add some delicious vegetables, some avocado, and a protein such as salmon. This meal will supply you with the necessary glucose, but in the right quantities that will optimise the functions of your body. The vegetables will be your multivitamin and mineral, the avocado will supply you with mono-unsaturated fatty acids, and the salmon will give you high quality protein as well as essential omega 3 fatty acids.

INTERESTING FACT:

Only carbohydrate containing goods have a GI value. (e.g. bread, pasta, grains, cereals, fruit, vegetables and legumes).

GI Values


White Bread
74

Brown Pita Bread
56

Seed Bread
55

GI Food Chart
G.I. Food Chart