Should I Eat Carbs?  

All living animals have energy needs, largely to fuel bodily functions and physical movement.  But where we should get this energy from is the subject of hot debate.  Carbs do provide energy, but they also serve other functions in the body, so let’s take a look at the science of fuel systems in the human body, where carbs fit in and our overall opinion on the inclusion of carbs in your diet. 

Energy For The Human Body 

The ultimate source of energy is the sun, which enables plants to make energy containing nutrients. 

Animals (including humans) can eat plants or other animals who have eaten plants to derive nutrients to provide energy.

Carbohydrates are the major energy containing constituents of plants and they are composed of carbon, hydrogen and oxygen.

Carbs are then often split into available and unavailable carbohydrates. 

Available Carbohydrates

These are digested and absorbed in the small intestine.  Their main function is to provide energy.

Most tissues in our body metabolise glucose for energy, but the brain and red blood cells have an absolute need for glucose.

Carbohydrates can be stored as glycogen in muscles and the liver, and these stores can be accessed when circulating glucose is low.  These stores do have a limit, so excess intake above energy needs is metabolised to body fat for energy storage.  Body fat can then be split into component parts and in a different process, converted back into glucose to fuel tissues in the body.

The type of fuel your body uses, largely depends on the activity you are engaged in. 

All energy in the body is produced by the breakdown of ATP, adenosine triphosphate.  ATP is found in all cells in all the body, but as it is a large molecule, not so much can be stored.  To restore ATP there are three relevant energy systems.  


In this system the body uses all the ATP it has stored in its cells.  This is the simplest energy production process and this is the system that your 100m sprint would utilise. 

Glycolytic System

This system runs on glycogen, which is the storage form of carbohydrates. This system provides moderate power and moderate duration.  Both the ATP-PC and Glycolytic system are anaerobic, meaning they don’t require oxygen to produce ATP.

Oxidative System

As its name suggests, this system does involve the use of oxygen to product ATP.  This system cannot produce energy as quickly as the other two, but it can produce it continually and for a longer duration.  This system can use stored carbohydrates and fats for fuel and this would be the system that the marathon runner would access.  

So as you can see, carbohydrates play an important role in fuelling, especially if you are active. 

But we have other types of carbohydrates, and they too carry out specific functions in the body.  

Unavailable Carbohydrates

Unavailable carbohydrates include fibre.  These foods aren’t digested in the stomach or small intestine, they reach the large intestine mostly intact and then provide food for the community of bacteria there.  As fibre is being broken down in the large intestine, short-chain fatty acids are produced (SCFAs).  

SCFAs play a role in:

  • Immune function, 
  • Intestinal health, 
  • Brain function, 
  • Mood, 

Low levels of SCFAs have regularly been linked to inflammatory bowel diseases and mood disorders like depression.      

Fibre feeds the microbiome and every day we are learning more and more about the link between the microbiome and various body systems.  Although there is much we still don’t know, we do know that fibre is important for optimal health. 

Aim for 30g of fibre per day; this can include fruits, veggies, nuts, legumes and more!

Carbs aren’t the enemy – it’s the type you eat.  Many carbs available to buy are heavily processed and refined, these are usually calorie dense but nutrient poor.  Wholefood sources of carbs can provide us with energy, and their fibre content can also support our health in other ways.

Some of our favourite carbs include:

  • Bananas, 
  • Quinoa, 
  • Sweet potato, 
  • Oats, 
  • Oranges, 
  • Blueberries, 
  • Lentils, 
  • Beans, 
  • Beets,