What are Carbohydrates?

Most people have some idea as to what carbohydrates are.  The word usually triggers thoughts of bread, pizza, and pasta, however, carbohydrates are found in the majority foods.  What differs however, is the type of carbohydrate found in those foods.  The aforementioned “carbolicious” foods contain high amounts of starch, a complex carbohydrate, whereas other foods such as lollies and fruit are higher in simple carbohydrates or sugars.

The Role of Energy Provider

Carbohydrates are not essential to human survival, although there is something to be said for the unfavourable effects of going too long without them.  Once ingested, carbohydrates are converted into glucose and then either used for immediate energy production, stored as glycogen (the storage form of carbohydrate), or converted into triglycerides and stored as body fat.

Simple vs Complex

Carbohydrates are often referred to as either simple or complex, but these “classifications” are more of a spectrum rather than distinct groups.

At the simplest end of that spectrum is the basic carbohydrate unit, a monosaccharide (literally meaning “one sugar”).  Common monosaccharides include glucose (primary fuel for your body) and fructose (sugar commonly found in fruit).  When two monosaccharides are linked together you get a disaccharide.  Common examples include lactose (milk sugar) and sucrose (table sugar).

Chains of monosaccharides greater than two units long are known as polysaccharides.  Some polysaccharides are still fairly simple, such as maltodextrin, while others are more complex, such as starch.

Why does it matter?  Longer chains of polysaccharides, particularly those that are highly branched, typically take longer for your body to turn into glucose, and therefore result in a steadier release of glucose into the blood.

Glycaemic Index

Glycaemic index (GI) is used as a measurement of the impact a food has on blood glucose compared to straight glucose.  As the standard, an equivalent dose of straight glucose is given the GI value of 100.  Generally speaking, foods high in simple carbohydrates with little fibre, protein, and fat, will have a high impact on blood glucose.  Hence why diabetics suffering acute low blood sugar, will use lollies to quickly boost levels back into the normal range.

How much does GI matter?

It is worth noting that the difference between straight glucose and polysaccharides such as maltodextrin and starch is rather small.  GI also does not take into consideration the amount of carbohydrate density of a food, the typical serving size of that food, or whether or not it is consumed with other foods; all of which can drastically affect the impact that food has on blood glucose levels.

Glycaemic Load

Glycaemic load (GL) is a unit of measure that also takes into account the amount of carbohydrate in a portion of food.  In other words, it combines “quality” (GI) with quantity (grams per serve).  Pumpkin for example has a high GI but a low GL.  Combining high GL foods (such as white rice) with low GL foods (such as broccoli) will reduce the GL of the entire meal.

Other Carbohydrates

Dietary fibre is a complex carbohydrate that the body cannot breakdown.  It provides ample benefits by increasing gut transit time, improving digestive health, and impacting the growth of probiotics in the gut.

Resistant starch is another type of carbohydrate which functions differently to standard carbohydrates.  As the name suggests, resistant starch is resistant to digestion, acting as more of a fibre than a starch.