Carbohydrates are the main food group from which the body sources its energy and it is during the metabolic process that the human body breaks the carbohydrates down to release energy.

All carbohydrates are made up of units of sugar, however they are categorised into two main sub types: i) simple sugars and ii) complex carbohydrates.

Simple Sugars
Simple sugars are just that – they are made up of one or two units of sugar and the easiest way to identify them is that they are sweet in taste. Glucose and fructose are the most common types of simple sugar; glucose is the primary form of sugar stored in the body for energy and fructose i the most common sugar found naturally occurring in fruits.

Sugar Types
• Sucrose: cakes, jam, pastries, sweets, puddings, ice-cream, chocolates, fizzy drinks.
• Glucose: sports drinks, syrups and manufactured foods.
• Fructose: fresh fruits and juices, tinned fruit, dried fruit and fruit puddings.
• Lactose: dairy products such as milk and yogurts.
• Maltose: found in malt and used for flavourings, particularly in breakfast cereals.

Complex Carbohydrates
In very basic terms complex carbohydrates are long chains of simple sugars bonded together. Starch is a prime example of a complex carbohydrate.

The bonds in these long chains of sugar units must be broken down before the sugar can be absorbed into the bloodstream and this occurs when an enzyme which is present in saliva gets to work when we eat. Once the sugar units, which are now glucose, has been absorbed into the bloodstream the body then either distributes it if energy is needed or stores it.

Starch Types:
• Potatoes, rice, pasta, couscous, noodles, cereals, crackers, grains, oats and barley.
• Pulses such as lentils, dried beans and peas which also contain substantial amounts of protein too.

Refined Carbohydrates
Refined carbohydrates are foods that have been highly processed and had some of their fibred removed during the process. These are less likely to have a low gi count. Examples include white bread, white rice and white pasta.

The Impact of Food on Blood Sugar Levels
As previously mentioned following a low gi diet helps to regulate blood sugar levels which is important for a number of reasons, these are discussed in more detail on The Benefits of a low GI diet page.

Foods that contain a high proportion of glucose release energy into the body very quickly causing the blood glucose level to shoot up but this also means that it drops very quickly too. This has a knock-on effect as when the low is experienced we feel the need to eat or drink again to raise the blood sugar levels again.

Whereas foods that a broken down more slowly during the digestive process release energy into the body at a steady rate meaning that we don’t experience the highs and lows and thus don’t need to snack as often as we feel more satisfied for longer.