by Dr Rosemary Stanton
What is the Glycaemic Index?
The glycaemic index (GI) measures how rapidly the carbohydrate in a food is digested to glucose and absorbed into the bloodstream. Each food is given a rating by comparing it with straight glucose which is assigned a GI value of 100. The lower the GI, the more slowly the carbohydrate in the food is absorbed into the bloodstream.
Low GI foods are important for those with diabetes because a 'dribble' of glucose into the bloodstream means the body needs only a small amount of insulin to clear the glucose from the blood. Some scientists believe that anyone at risk of developing diabetes - which includes those with excess fat around the waist - should also choose foods with a low GI.
Only foods that have at least 10g of carbohydrate in a serving have a GI. Most vegetables have too little carbohydrate to have a GI and meat, eggs, fish and chicken have no carbohydrate and so don't have a GI.
- low GI foods means GI less than 55
- moderate GI means GI from 56-69
- high GI means GI greater than 70
Low GI foods for children?
The brain uses glucose as a fuel and studies show that concentration is better when blood glucose levels remain steady. Low GI foods are ideal because they provide a slow steady release of glucose into the bloodstream. However, it's important to also consider the overall healthiness of a food. A low GI junk food is still a junk food.
Low GI food ideas for home
These foods are healthy and have a low GI:
- Sandwiches or rolls made with wholegrain bread
- Corn on the cob
- Hummus with carrot and celery sticks
- Fruit loaf, fresh or toasted
- Tabbouli salad
- Pasta salad or hot pasta dishes
- Brown rice salad
- Soups with beans (eg minestrone)
- Fresh fruit
- Dried fruit
Fruits and vegetables and GI
Of the vegetables that have enough carbohydrate to have a GI, the lowest values are in peas, carrots and sweet potatoes. Waxy potatoes that won't mash and are used for potato salad generally have a lower GI than other varieties.
Most fruits have a low GI, especially