Saturday, May 1, 2010

Carbohydrates debunked

Refined carbohydrates - better than you think!

Mixed messages about carbohydrates and their effect on the body are common in the media, with research findings sometimes contributing to further confusion. Carbohydrate foods such as bread and rice have been staples from ancient times for many cultures, but today there are many misconceptions about how and when they should be eaten or even if they should be eliminated from the diet. Avoid eating carbohydrates after a certain time of the day as you won’t burn them off or opt for low glycaemic index (GI) carbohydrate choices - does this sound familiar, the dos and don’ts of eating? Carbohydrates are often linked to causes of obesity and other chronic illnesses, but are other underlying factors responsible?

Carbohydrates are an important source of energy for the body, particularly the brain, nervous system and red blood cells. They are found in many foods we eat in different forms ranging from those closest to their natural form (oats, rice, legumes), to those that have been processed to allow eating and digesting more readily (bread, pasta, breakfast cereals), to those that are considered more a ‘treat’ (sugars, sweet biscuits, soft drinks).

Carbohydrates should contribute approximately 45-65 percent of the energy in a healthy diet. Healthy carbohydrate options include grain-based foods like bread, breakfast cereals, rice, pasta, noodles and legumes, starchy vegetables, fruit and milk products. Cutting out these carbohydrate foods does not make good sense as they contribute important nutrients including protein, dietary fibre and essential vitamins and minerals such as iron, folate and thiamin. Wholegrain varieties also contain many components that can promote good health.

‘Not so healthy’ carbohydrate foods such as soft drinks, cordials, fruit juices, lollies, cakes, doughnuts, sweet biscuits and pizza add few if any nutrients to the diet and may be inappropriate sources of energy on a regular basis.

Carbohydrates and health

Carbohydrates have differing effects on blood glucose levels depending on the type and quantity eaten. The carbohydrates in foods with a high glycaemic index (GI) are digested rapidly whereas those in low GI foods are slowly digested. A low GI diet is generally encouraged but a healthy diet can include both high and low GI foods.

A small number research studies have shown an association between a high GI diet and increased risk of disease such as heart disease. On closer inspection the carbohydrate food sources in such studies are not always representative of healthy options but often include less healthy options such as sugar, honey, jam, pizza and cakes. These foods are often higher in saturated fat, with up to double the amount recommended by health authorities which could also attribute to health outcomes. Other factors which may influence study outcomes, but are not always accounted for, include body weight, smoking, exercise, alcohol consumption and stress management.

When considering the pros and cons of eating carbohydrates, nutrient content should be considered as well as the GI. Carbohydrates foods such as breads, cereals, rice, pasta and oats provide a range of important nutrients. Refined varieties are lower in nutrients than wholegrain varieties but can make a nutritionally important contribution to a healthy diet. Carbohydrate foods such as soft drinks, confectionary, cakes and sweet biscuits provide minimal nutrients and are not a suitable part of a healthy diet on a regular basis.

Australian dietary guidelines recommend 4+ serves a day of grain-based foods such as breads, breakfast cereals, rice, pasta and crispbreads, and it is good practice to make at least half of these wholegrain. Variety is important, so choose from all food groups daily, with less healthy ‘treats’ eaten only occasionally.