GI - Glycaemic Index

Glycaemic Index, or GI for short, is a relatively new term in the nutrition world. A food’s GI indicates the rate at which the carbohydrate in that food is broken down into glucose and absorbed from the gut into the blood. In high GI foods, this occurs quickly, causing your blood glucose (sugar) level to rise rapidly. In low GI foods, carbohydrate is digested slowly resulting in a more gradual rise in blood glucose levels.

Some examples of low GI and high GI foods include:

Low GI High GI

Wholegrain bread

White and some wholemeal breads

Chickpeas, kidney beans, lentils

Rice cakes

Milk, Yoghurt

Honey

Apples, pears, grapes, kiwifruit

Watermelon

Pasta, noodles

Short-grain white rice

Oats, bran

Puffed wheat, cornflake, rice flake cereals

If you would like to find out the GI of a particular food, look it up on the database at www.glycemicindex.com

GI is an important tool when choosing a balanced diet for long term health, although, on its own, GI does not make a food ‘good’ or ‘bad’. Some high GI foods, such as hot potatoes and fresh watermelon, contain many valuable nutrients, while some low GI foods, such as chocolate and corn chips, are far less beneficial containing large amounts of saturated fat and sugar.

We rarely eat only one food. When foods are eaten as part of a meal, the GI is affected by other components of the meal, including the amount of protein and fat being eaten, the types of starch and fibre. If you eat low GI foods in a meal, this will reduce the overall GI of the dish. For example, eating rice bubbles (high GI) and milk (low GI) for breakfast would be considered moderate GI.

Eating mainly low GI foods everyday is encouraged as it provides a slow, continuous supply of energy from one meal to another. For those wanting to lose weight, low GI foods as part of a balanced diet may be helpful. The carbohydrate in low GI foods is digested slowly, making you feel fuller for longer. Regardless of GI though, it is still important to consider the amount eaten. Most people need to eat less calories and become more active when trying to lose weight.

People who have diabetes can use the GI of foods to help control blood glucose levels. For more information about how GI can assist those with diabetes, visit www.diabetes.org.nz.

If you play sport, looking at the GI of foods can help you make choices to aid performance. While you are exercising the blood in your body is pumped to the muscles, lowering the available supply. At this time, you need high GI foods, giving energy quickly, such as lollies, ripe bananas and sports drinks. Eat low GI foods for a great energy base prior to exercise – such as baked potatoes or porridge. Our sports nutrition page has more information on foods for exercise.

Tips

  • Include a mix of nutritious high and low GI foods in your everyday eating.
  • Aim for an overall lower GI by increasing the amount of low GI foods such as legumes (beans, peas and lentils), fruits, oat, cereals and pasta in your meals.
  • Choose multigrain breads instead of white, and breakfast cereals based on oats and bran.
  • Try low GI grains - basmati or Doongara rice, pasta, noodles or quinoa.

 

 

 

Photo: vegetables.co.nz