The glycaemic  Index is a ranking of foods from 0-100 that shows how quickly your body breaks them down into glucose – your main source of energy. GI was originally devised to help diabetics to manage their blood sugar levels.  Now,  it is a popular management device and a good way of choosing the right foods to eat before and after exercise.

Carbs need to be digested and broken down into their simplest form, glucose, before they can pass through the walls of the intestine and get into the bloodstream to provide energy. Foods that are digested rapidly and create a large sugar  increase in your blood are seen as being high on  the GI;  foods that release their energy slowly are low on the GI.

Refined carbs,  such as white bread, shite pasta, cakes and biscuits  will cause a rapid rise in the blood glucose and insulin levels. This surge in insulin will  at first give you an instant rush of energy, making  you feel great, but is quickly followed by  an energy slump, making you feel lethargic and hungry. These fluctuations in blood-sugar levels also cause the body to store fat more readily.

However, you don’t need to avoid  high GI foods altogether. High GI foods are handy if you need a quick energy surge immediately before hitting the gym.

Carbs that take a  long time to  be digested before releasing a gradual  energy are known as moderate or low GI foods. These foods such as bananas,  oatcakes and porridge, generate a gentle blood-glucose rise, which keeps you feeling fuller and energised for longer. Many experts recommend eating a low GI  meal two or three hours before hitting the gym.

Low GI foods also enhance your fat-burning  process, so they will help you stay trim, too.

Finding which the GI of food isn’t always that simple. You can check  http://www.glycemicindex.com/ website or check the labelling system used by many supermarket.  If the rating isn’t obvious then it’s always worth remembering that the truer the food is to its  natural state, the more likely it is to have a low GI.