In Defence of Carbohydrates

Carbohydrate is a dirty word these days. But why is this the case and why are carbs so maligned? Some even consider them to be the big bad wolf of the nutritional world.

Just in case you need it, here’s a refresher: Carbohydrates are found in highly nutritious food like bread and cereals, fruit, starchy vegetables, milk and yoghurt as well as legumes and beans. But they’re also found in less nutritious food like lollies, chocolate and cakes, pastries, and drinks like soft drinks, cordials and fruit juices.

So, what happens in your body when you eat a bowl of pasta, a sandwich, an apple or even a chocolate milkshake? Well, the carbs in these foods undergo a series of metabolic processes beginning in the mouth and ending in the small intestine where they finally produce glucose (a form of sugar). These glucose molecules cross the small intestine and eventually find their way into the muscles and brain cells, where they are used as energy with the aid of insulin, (a hormone that is released by the pancreas). Any excess glucose can be stored in the liver, but the liver has a limited capacity to house it – about 150 grams all up.   

So, why is there a common belief that eating carbs makes you fat? Sure, eating too much of anything will likely lead to weight gain. That simple equation of ‘energy in versus energy out’ rings true. But why are carbs so often made the scapegoat in this debate? Perhaps there is a misunderstanding of the biochemical processes that occur when we consume food.

When we eat foods we generally don’t just eat one nutrient in isolation. My lunchtime sandwich is a case in point; it typically contains cheese, tuna and avocado, a combination of carbs, fat and protein. The protein component is involved in muscle recovery and building, but it can be used as an energy source if needed. Meanwhile, the fat and carbohydrates will be broken down for energy or stored in the body to be used as fuel at a later stage when there is a need to rely on energy reserves. Keep in mind that we have an endless capacity to store fat, whereas carbohydrate storage is greatly limited. Nevertheless, carbs are the body’s preferred fuel source and the body would rather use them to keep it running effectively and efficiently. So the carbs from my sandwich will be predominately burnt for fuel, whereas only a small percentage of fat from the cheese and avocado will be broken down during this time. However, once the carbs are metabolised the body will predominately turn to the fat from the meal to fuel it. Therefore, if you over-consume carbs in the presence of fat, your body will preferentially break down more carbs and less fat. Subsequently, if you’re body doesn’t churn all that fuel, it will likely store the excess as fat. That cycle can be repeated over and over again resulting in lots of excess fat being stored. That probably goes some way to explaining Santa Clause’s portly belly – too much milk and too many cookies!

This beckons the question, should we avoid carbs altogether so our bodies burn the fat, therefore, ending the obesity epidemic? Well, no. It isn’t that cut and dry. If only. It is important to note that the process of fat metabolism is dependent on a by-product of carbohydrate metabolism. And more than that, carbohydrate foods such as whole grains, fruit and starchy vegetables as well as beans and legumes contain these wonderful things called vitamins, minerals, phytonutrients and fibre, which are brilliant for promoting optimal health. Good luck meeting your fibre requirements if you totally exclude these types of foods.

But, then what nutrient is to blame for the obesity epidemic and the high rates of diabetes and heart disease currently crippling so many Australians? Well, it would seem that we can’t simply blame one particular nutrient or food group over another. However, one issue is clear, we are eating FAR TOO MUCH. Carbs, fat, protein and grog – we are simply downing too much of all these things. The 2011—13 Australian Health Survey revealed that the average adult man consumed 9,655 kilojoules each day while the average woman consumed 7,402 kilojoules every day. And based on the statistics on obesity these findings would indicate that we are by and large taking in more energy than we need. That, and we’re not exercising enough.    

So, with that knowledge, what are we to do? You could start by keeping your portions in check, eating more fruit and veggies as well as lean meat and dairy and eating less processed foods and going easy on the discretionary foods including booze. And get moving. It isn’t rocket science.