Glycaemic Index


The Glycaemic Index (Gi) is a ranking of foods from 0 to 100 according to how quickly each food (when eaten on their own and on an empty stomach) will raise blood sugar levels.

You might find Gi foods ranked as low, medium or high on the packaging of foods you buy.  Foods with a low Gi can help stop that feeling of hunger between meals, so are often used by people trying to lose weight. 

Carbohydrate foods with a low Gi

  • Usually more nutritious
  • Release their energy slowly
  • Satisfy your appetite for longer
  • Are more bulky

How to use them

  • These foods help you to regulate your food intake and stop you getting hungry
  • The majority of your carbohydrate intake should be from these foods
  • They can be used to help you raise your all important glycogen stores in the days before an event
  • They help sustain energy levels for longer

For example a bowl of porridge in the morning can give an athlete plenty of energy for moderate activity until lunch-time.

Carbohydrate foods with a high Gi

  • Are more processed
  • Usually contain fewer vitamins, minerals and fibre
  • Give you an instant burst of energy
  • Can cause tooth decay

How to use them

  • Sparingly, but they can be used to take on extra energy at half-time during a team match or to help refuelling after you have finnished your sport
  • You only need these foods if you are exercising hard for an hour or more, or at times when you need to perform at your very best  

For example if you are competing in a swimming event with several heats you might want to take on board medium to high Gi foods between heats e.g. a banana, jaffa cakes or a small amount of dried fruit to help keep your energy levels up.  Don't forget these foods contain sugar and so you should remember to brush your teeth regularly twice a day with a flouride toothpaste.

Low Gi Foods

These carbohydrate foods can be used to help you refuel between training and events:

Grapes, oranges, apples, kiwi fruits, pears, peaches, grapefruits, plums, cherries and dried apricots, avocados, peas, green, leafy vegetables and most other vegetables, white and wholegrain pasta, porridge and oatmeal, wholegrain rye bread (including pumpernickel), lentils and beans, soya products, milk and yogurt.

Medium Gi Foods

These carbohydrate foods can be used to help refuel between training and events:

Bananas, figs, dried dates and raisins, fresh dates and mangoes, carrots, sweetcorn, new potatoes, wholemeal bread, rye-based crispbreads, couscous, wholegrain cereals, basmati rice, brown rice. and chocolate.

High Gi Foods

These carbohydrate foods are great for a quick burst of energy during sport or for refuelling afterwards:

Glucose, sweets, still and fizzy drinks, watermelons, mashed potatoes, parsnips, squashes and swedes, white bread, rice cakes and white rice.


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