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Why do we need carbohydrates for energy?

Carbohydrates are your body’s most preferred source of energy and one of the most important macronutrients your body needs to function. Carbohydrates are the sugars, starches, and fibres found in foods such as fruits, grains, vegetables, and milk products. Carbohydrates are often margined in trendy fad diets yet they are extremely important to maintain a healthy diet.

Carbohydrates provide fuel for the central nervous system and energy for our hard-working muscles. They also prevent protein from being used as an energy source -which is not what you want to happen because the body needs protein to build muscle (lean body mass). Using protein instead of carbohydrates for fuel will put significant stress on the kidneys.

Carbohydrates are not only used for our muscles but also for brain function. In the human body, carbohydrates are broken down into smaller units of sugar such as glucose, fructose then is absorbed into the small intestine which from there enters the bloodstream and travels into the liver. The function of the liver when this happens is to convert these sugars into glucose which is carried by the bloodstream (accompanied by insulin) and then converted into energy for basic body functioning and physical activity! When carbohydrates are withheld in diets it can make a huge impact on mood and memory. Two recent studies published in the journal Proceedings of the National Academy of Sciences have also found a strong correlation between carbohydrate intake and decision making.

Something to keep in mind when consuming carbohydrates is to remember that not all carbohydrates are the same! If you have been keeping up to date with our recent blog posts you will know what the terms ‘simple carb’ and ‘complex carb’ are. For you newbies, we will quickly break it down for you. Generally speaking, the two types of carbohydrates are different due to their chemical structure and how quickly the sugar is absorbed, digested, and used for energy. Simple carbs (e.g candy, soda, refined sugars) are absorbed and digested far more quickly than complex carbs or polysaccharides that have three or more sugars (e.g potato, whole-grain bread, cereals). While all carbohydrates release energy sources complex carbohydrates provide sustained energy and don't lead to spikes in blood sugar levels and sugar highs like simple carbohydrates do.

Not getting enough carbohydrates can cause issues because when your body is without sufficient fuel the body has no energy. Without sufficient glucose, the central nervous system suffers which may cause dizziness and mental and physical weakness.

So remember this the next time you think you need to give up carbohydrates to lose weight when as a matter of fact you need carbs to be able to get through your exercise sessions and perform your best too.



Stubbs, R. J., Prentice, A. M., & James, W. P. T. (1997). Carbohydrates and energy balance. Annals of the New York Academy of Sciences, 819(1), 44-69.

Livesey, G. (1995). The impact of complex carbohydrates on energy balance. European journal of clinical nutrition, 49(3), S89.

Mann, J. (1987). Complex carbohydrates: replacement energy for fat or useful in their own right?. American journal of clinical nutrition (USA).

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