What the hell are carbs, and why do you need them?

When it comes to cycling, carbohydrates are a bit of a buzzword; when you’re gearing up for a ride, you’re either carboloading, or carbing up. If you’re riding or racing, you’re ‘gettin’ those carbs into ya’ via some gelatinous fluid that generally tastes like you’d rather the suppository form, and when you’re finished, you’re consuming recovery carbohydrates so you’re ready to go again ASAP. But what exactly are carbohydrates, and are they actually good or bad?

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As the name suggests, carbohydrates are hydrated carbon chains, meaning they contain hydrogen and oxygen. Carbohydrates come in many forms and have a variety of roles, from energy storage to the upkeep of your genetic information. One of the defining characteristics of carbohydrates is their ability to link together with other carbohydrate molecules to form immense chains, in a similar way to train carriages. These chains can be anywhere from one unit long, known collectively as monosaccharides, to 30000 units long, known as polysaccharides. Monosaccharides, more commonly known as simple carbohydrates, include glucose and fructose. Polysaccharides are complex carbs, such as starch, and are found in bread, cereals and pasta.  Simple carbs differ from complex carbohydrates in the way they are stored in the body.  Complex carbs require enzymes to break them down to their monosaccharide form, which isn’t a process required for simple carbs.

Carbohydrates are the immediate energy supply for your muscles, providing far more bang for your buck than protein or fats. 

However, cyclists aren’t just interested in carbohydrates because they have different carbs to match every intellect, it’s because of the advantage they can provide as a source of fuel for the body. Carbs are an immediate energy supply for your muscles, providing far more bang for your buck than protein or fats.

When you consume carbs, they are stored in your skeletal muscle and your liver in the form of glycogen. Glycogen is a molecule formed of many individual carbohydrate units. The more individual units, the more energy is being stored. When required, glycogen can be broken down by a process known as glycogenolysis, to generate a compound known as G6P. From here on, the rest of their journey leads to far more incomprehensible technical jargon, but what we do need to know is that it gives us energy to spin those cranks.

1280px-Glycogen_structure.png

-A ball and stick structural model of glycogen, built around a glycinogen peptide chain. 

Carbs are often grouped into two groups: good or bad. This black-and-white view on the morality of carbohydrates is not only biologically incorrect, but it also limits your training if you don’t understand what it all means. This good vs. bad judgement is loosely based off a more scientifically accurate scale known as the glycemic index (GI), a test which indicates the speed at which carbohydrates release their sugars into your blood stream. Low GI foods (aka. the good) release carbs slowly, and high GI foods (aka. the bad) releasing them quickly. However, the index actually scores food in a range between 1 to 100, with most foods being clustered around 70, so it’s a much more complex classification than simply labeling carbs as either good or bad.   What is interesting is that the complexity of the carbohydrate has no bearing on the GI of the compound. For example, the GI is measured against, at least in Australia, 50 grams of pure glucose, the highest standard result. However, fructose, another monosaccharide, has one of the lowest GI scores, at around 50.

You can utilise the different types of carbohydrates to maximise your training, but for now, the most important thing to remember is to eat a healthy, balanced diet, and be sure to take some form of carbohydrates with you on your long rides.

References

Häggström, Mikael. “Medical gallery of Mikael Häggström 2014“. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.008ISSN 

William D. McArdle; Frank I. Katch; Victor L. Katch (2006). Exercise physiology: energy, nutrition, and human performance (6 ed.). Lippincott Williams & Wilkins. p. 12. ISBN 978-0-7817-4990-9.

About Tim_Davis@Pushys

I'm a Science Graduate and Medical student at the University of Queensland, specialising in anatomy and physiology. More importantly, I'm all for any type of riding; road, mountain, dirt jumping, I love it all! Let me know if there is anything you want to know about nutrition and health, and I'll do my best to help you out!

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