Carbohydrates

Published by Bupa’s Health Information Team, December 2010.

Carbohydrates seem to have been given a bad rap in recent years. Say the word ‘carbs’ and for many people, stodgy food and weight gain spring to mind. But in reality, your body wouldn’t be able to function without carbohydrates. This article looks at why this nutrient is such an important part of our diet.

What is carbohydrate?

Carbohydrates are compounds that your body uses for energy. They are found in almost every type of food you eat – albeit in different forms and amounts. All carbohydrates are made up of individual ‘building blocks’ or sugar molecules. The most basic carbohydrates – such as the sugar you put in your tea, or that gives your apple its sweet taste – consist of just one or two of these molecules.

Other more complex (or ‘starchy’) carbohydrates are made up of a number – sometimes hundreds – of sugar molecules joined together. These are the types of carbohydrate found in bread, pasta and rice, as well as some types of fruit and vegetable.

Fibre is also classed as a carbohydrate. However, unlike other types of carbohydrate, it isn’t usually used by your body for energy but has a number of other important functions. Read our related article for more information on fibre.

Why do I need carbohydrate?

Carbohydrates are your body’s main source of energy. You use them as fuel, not only to help you walk or run, but also to keep your heart, lungs and other vital organs working properly.

When you eat any type of carbohydrate, it’s broken down by your digestive system into single molecules of glucose – the main form of fuel for your body. The glucose is then circulated in your blood to every cell in your body.

If you don’t have enough carbohydrate in your diet, your body will start to break down fat and then protein to get the glucose it needs. Protein is important for your body to be able to grow and repair itself, so using it as an energy source means there will be little left to carry out these vital functions. Eating enough carbohydrate will prevent this.

Good carbs, bad carbs

There has been much misconception in recent times that carbohydrates are fattening. Of course, as with many things, it’s not good to have too much. If you eat more carbohydrate than your body can burn off as energy, your body’s glucose stores will become saturated and the excess will be converted to fat. In other words, you will start to put on weight. But carbohydrates are an essential part of a healthy diet. The key thing is picking the right type of carbs. Some types of carbohydrate are healthier than others.

Sugar-rush

Foods and drink that are high in sugar are a key cause of tooth decay. Sugary foods such as cakes and biscuits also tend to be high in fat, but they often don’t contain many other useful nutrients – hence the term, ‘empty calories’, as they contribute to your energy intake but have little other value. Not only that, but sugary foods are often very energy dense, which means they pack a lot of calories into a small volume. Eating just small amounts of these foods can push up your calorie intake. It’s therefore best to limit your intake of sugary foods and stick to starchy foods.

Wholegrains for health

In general, the best starchy carbohydrates to go for are wholegrain foods – including breads, pasta and cereal. Wholegrains contain a host of important nutrients that are thought to reduce your risk of heart disease and bowel cancer. When grains are processed (or ‘refined’) to make them look whiter, the part of the grain that contains fibre and many useful nutrients is removed. This means that white bread, pasta and cereals aren’t as beneficial to your health.

Wholegrains are also more likely to keep you feeling fuller for longer – as they generally take longer to digest than foods that have been processed and contain more fibre. This can help to control your appetite, helping you to maintain a healthy weight.

How much carbohydrate do I need?

It’s thought that at least half the energy in your diet should come from carbohydrates. Many people in the UK are already eating enough, but it’s often the wrong type – with too much coming from sugary or refined products and not enough from wholegrain, starchy foods. Starchy foods should make up about a third of your diet. The easiest way to do this it to try and include some at every meal – and opt for wholegrains when possible.

Although it’s best to limit the sugar in your diet, this doesn’t mean cutting out fruit. The natural sugars in fruit are not as bad for your teeth as those in sugary foods and drinks, as they are held inside the cells of the fruit and only released when you chew the fruit, or if the fruit is juiced or blended as in fruit juices and smoothies. If you drink these, try to stick to one a day and drink them with a meal to reduce your risk of tooth decay.

Get into carbs

Most people aren’t eating enough starchy foods. Here are some tips on how you can get good carbohydrate into your diet.

• Cut down on refined carbohydrates if you can – swap your white bread, pasta and rice for wholemeal or wholegrain and granary versions.
  
• Variety is the spice of life – try a bagel, tortilla wrap or ciabatta as alternatives from the usual bread. Sweet potatoes and yams make a change from plain old potatoes.
  
• Aim to increase the carbohydrate in your meals and reduce the amount of fat or protein – you could replace meat in casseroles, stews and curries with beans or lentils for a carbohydrate-rich, low-fat meal.

For sources and links to further information, see Resources.