Revealed! The truth about carbs

Carbohydrates are a bit like life - sometimes simple and sometimes complex. 

Either way they are a key fuel that your muscles go to for energy. And it's ultimately the simplest carbohydrate of all they need - glucose.

Whether you consume your carbohydrate as simple sugars or as more complex starches such as pasta and rice, they all get broken down by digestion into glucose, which your body's tissues all use as their primary source of energy.

Although the simplest carbohydrate is glucose, other sugars include sucrose (the familiar sugar that we tend to use on a day-to-day basis), lactose which is found in milk, and fructose - the sugar found in fruit.

Carbohydrates with a more complex molecular structure include starchy foods such as bread, pasta, rice, lentils and beans which in their unrefined state are also high in a third kind of non-digestible complex carbohydrate which we all know as fibre.

Ultimately, all digestible carbohydrates are broken down to glucose during the digestive process and either transported in the blood to the body's tissues for immediate use or stored in the liver and muscles.

How much carbohydrate do you need?

At least half of your energy intake should come from carbohydrates (the rest coming from fat and protein) with as much of this coming from complex, unrefined carbohydrates as possible.

Unfortunately, although we tend to get sufficient carbohydrates in our diet, too much of these typically come from simple sugars either contained in the food and drinks we consume or added during preparation.

In order to maintain a healthy diet, you should therefore try to minimise as far as possible your intake of sugars and sugary foods and drinks and focus instead on more unrefined, complex carbohydrates.

Choosing the right carbohydrates

It's important to maintain a steady intake of slow-releasing carbohydrates in order to avoid sudden increases in blood glucose levels. This can cause your pancreas to over-react to correct the glucose levels resulting in a glucose low an hour or two later.

When considering your options for carbohydrate intake you should therefore remember that more complex carbohydrates will generally break down to glucose in the gut - and be released into the blood - far more slowly, resulting in steadier blood glucose and energy levels.

The Glycaemic Index - keep it low and slow

Certain factors will affect how quickly carbohydrates are broken down and the Glycaemic Index (GI) is a scale ranking from 1 to 100 that indicates the rate at which this happens.

For example, simple carbohydrates can be turned into glucose more rapidly giving you a 'sugar rush' and these have a higher GI - while complex carbohydrates such as whole grains have a lower GI because they are broken down into glucose much more slowly.

The GI of a food is also dependent on how refined the carbohydrate is as a result of the manufacturing or preparation processes it goes through. White rice, for example is a complex carbohydrate but because it's refined from brown rice by removing its fibrous husk its GI is increased.

What really counts is the overall combination of the foods you're eating at the time. You can lower the overall GI of your meal by ensuring that you have at least some complex carbohydrates included - having some fibre on the plate also significantly slows down the absorption of glucose from other more refined or sugary foods.