Australasian Science: Australia's authority on science since 1938

The Truth About Carbs


Most Australians do not eat a high carbohydrate diet, but many eat too much refined carbohydrate with a high GI.

By Alan Barclay

Hardly a week goes by without some new study proclaiming the negative health effects of carbohydrates in our food, but are carbs really that bad for us?

The full text of this article can be purchased from Informit.

Carbohydrate is an essential nutrient like protein, fat, vitamins and minerals. It is the only fuel used by our brains, kidneys and red blood cells, and the preferred fuel of our muscles.

All of the carbohydrate we consume in food is digested in the stomach and small intestine, where it is broken down into glucose, fructose and/or galactose. These sugars are then absorbed through the walls of our intestine and end up in our bloodstream.

Most glucose circulates throughout the body, providing fuel for our red blood cells, brains and muscles. Glucose can be stored in our muscles and liver as glycogen, and is converted back to glucose for energy in times of need (such as when you are exercising).

Fructose and galactose are extracted from the blood as it passes through the liver, where they are also converted to glucose that can either be released into the blood, stored as glycogen or converted to pyruvate, which is released into the bloodstream as an alternate fuel source. If very large amounts of pure fructose (>50 grams) are consumed in a single “dose” it can also be converted to fat, although this is thought to make up a relatively small fraction (<1%) of the amount consumed in humans.

Ultimately, all carbohydrate is converted to ATP (adenosine triphosphate), which the body uses as energy. Carbohydrates provide the least number of...

The full text of this article can be purchased from Informit.