The Benefits of Carbohydrates Pre and Post Workout

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By Lauren Killey

Carbohydrates are one of the key macro nutrients (along with protein, fat and to a lesser extent, fibre, water and alcohol). Carbohydrates, in particular, are our body’s primary, preferred energy source. Think of carbs like the petrol that goes into our car – we aren’t going anywhere too quickly, without them.

When consumed, carbs will be broken down and converted into GLUCOSE before entering the blood stream. From here, our body will produce its fuel and stored energy. This glucose will either:

Be taken into the body’s cells and converted into a fun little thing called ATP (adenosine triphosphate) – through a process called cellular respiration. Our cells will then use this ATP to power the majority of our metabolic tasks, eg: given us the energy we need to go about the movements of our day.

If we have enough glucose to give us all the energy we need, or to fulfil our daily energy requirements, this glucose will be converted into something called glycogen (a bit of a ‘key’ word in the bodybuilding and fitness competition world on show day). This glycogen will be stored in the liver and our MUSCLES. The liver will hold around 100g of stored glycogen. Our muscles storage capacity will differ for a multitude of reasons, between individuals, but the average equation we can use to find our muscle glycogen storage capacity, is 7 x LEAN body mass. The glycogen stored in your muscles, will ONLY be used by the muscles and is vital for longer periods of higher intensity exercise.

The benefits of carbs:

  • Stored glycogen helps to preserve muscle! Limited stored glycogen can lead to the break down of muscle into amino acids to generate needed energy. If you want to maintain your muscle you need a certain level of carbs!
  • Carbohydrates are our body’s preferred energy source! The body is proficient at the process of converting glucose into ATP – why fix what isn’t broken?
  • The body requires carbs to function – we need around a minimum of 120g worth of carbohydrates for optimal cognitive function 
  • Carbs help with SLEEP and STRESS. Carbs will increase serotonin (happy hormone) and can decrease cortisol and adrenaline (stress hormones). This is why, when we are feeling down or highly stressed, we can crave carb heavy foods, it’s our body’s survival mechanism to make us feel better! Carbs are also an essential part of the unwind process, aiding in the production and conversion of melatonin (our sleep hormone.) SO, they decrease stress, make us feel good and help us to unwind.
  • Carbs aid in optimal digestion. Specifically, dietary fibre. This is not broken down into glucose and will pass through the body as either soluble or insoluble fibre to improve digestive processes and aid in optimal gut health.
  • When training, we deplete our body’s stored glycogen. So, this is why we recommend a carb meal pre and post training. To boost our ATP and ‘need-now’ energy along with refuelling the stored energy in our muscles once we have used up this glycogen when training.

The take-away?

If you want to ensure you are making the most of your daily energy and cognitive function, you need carbs! Our body will break down carbs to provide instant, and stored energy, help negate the breakdown of muscles and provide better digestion and gut health. Though our body is very good at adapting, and can survive without carbs through a process known as gluconeogenesis (the conversion of protein into glucose) or ketosis (the conversion of fats, into energy) neither are optimal long term and neither will provide the brain the glucose it needs!


Want to upskill yourself in the science of nutritional biochemistry and the interaction of protein, fats, carbs along with how they influence the body to maximize client results? ⁣⁣
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  1. Brain Serotonin, Carbohydrate-Craving, Obesity and Depression, R J Wurtman 1, J J Wurtman, 1995:,protein%20intake%20lacks%20this%20effect.
  2. Effects of Diet on Sleep Quality1 Marie-Pierre St-Onge,* Anja Mikic, and Cara E Pietrolungo, 2016
  3. Increasing Dietary Carbohydrate as Part of a Healthy Whole Food Diet Intervention Dampens Eight Week Changes in Salivary Cortisol and Cortisol Responsiveness Hoda Soltani,1 Nancy L. Keim,1,2 and Kevin D. Laugero1, 2019:,latency%20have%20also%20been%20affected. &,to%20prolonged%20exercise%20%5B64%5D.

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