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Fuelling the Body: The Basics

As a young man who has played sport all his life and has a degree in Sport & Exercise Science I am fortunate enough to have a good understanding of the food I put in to my body, what I need, and why I need it. But, unfortunately having worked with a lot of athletes, young and old, a lot of people are absolutely clueless on what constitutes a healthy diet. Why is that? Is it because people want to be overweight or malnourished? Do people want their organs to be working overtime because they have pumped too much sugar in to the bloodstream? Do athletes want to feel bloated or tired when they are competing?

Well there are a few strange people in the world, but for 90% of us the answer is a big fat NO! The problem is that there is no education on nutrition in school, no-one telling us how the human body functions and what it needs to turn us in to Dwayne 'The Rock' Johnson (that won't happen by food alone, unfortunately). If I asked the question, what are macronutrients? I don't believe half of the population would be able to answer the question. What if I then asked "what is the role of the different macronutrients in the body?" Then I might get a few bewildered looks. The problem is that while all our time is being spent on the traditional subject of maths, English and the sciences there is no time in school spent on real life skills such as, looking after the human body and staying healthy. The lack of funding and time spent on teaching children these skills is only coming back to bite the government in the ass as it is one of the key contributors to obesity and associated chronic diseases such as: diabetes, cardiovascular diseases and cancer. Obesity is one of the greatest causes of death globally. In 2014 more than 1.9 billlion adults, 18 and over were overweight, of these 600MILLION were obese.


Don't get me wrong, as humans we are greedy, we see something we want and struggle to control our desires to have it. Even though we know we don't need it, or even worse, its actually bad for us. But nonetheless, by educating the human race just a little bit more on the topic of nutrition then people can make a more educated decision about throwing processed junk foods in to the body.

Enough ranting with no raving! Lets learn a little about the three basic macronutrients that provide our body with energy to sustain the many chemical reactions that go on in the body and allow us to carry out our day to day tasks.



  • What actually is Fat? 90% of Fats in the body are Triglycerides (3 fatty acids and glycerol combined together) . The human body then breaks down triglycerides into separate components where free fatty acids diffuse into the blood and are transported to the muscle. Free fatty acids are then entered in to the Krebs Cycle where they are converted to ATP to produce energy the body can use.

  • Like protein, but not carbohydrates, fat is essential to human life, fat is NEEDED in the diet. Fat is what provides fuel for the body throughout 90% of the day as it is the most concentrated source of energy, with 1 gram of fat providing 9 calories (5 more than that contained in protein or carbohydrates)

  • However to use fat as fuel for the body we require oxygen available to go through the long process of many chemical reactions that provides us with ATP (only usable form of energy in the body), when exercising at high intensities (usually above lactate threshold or more specifically where we a producing more carbon dioxide than we are taking in oxygen) we are unable to use fat as a source of energy and instead must use carbohydrates (primary energy source).

Fat is an essential macronutrient and has numerous benefits on the human body.

  • At provides a cushion to help protect our vital organs – without fat our organs would be more prone to damage. Furthermore, fat acts as an insulator, helping us to maintain the correct body temperature.

  • Fat enables our bodies to process vitamins A, D, E and K, which are all fat soluble and vital to good health. (More on Vitamins)

  • Like amino acids in protein, fat contains essential fatty acids (EFA’s). These EFA’s are, as their name suggests, essential to good health and likely to help the heart and immune system. The human body cannot make its own (synthesize) these EFA’s and therefore has to get them from consumption of fat.

  • Some fatty acids – like omega 3 – may provide other health benefits such as complimenting the cognitive processes of the brain.

Fats can be split into 2 main categories

  • Saturated

  • Unsaturated

Approximately 30% of an athlete’s caloric intake should come from fats.

Whilst not as beneficial as unsaturated fats, there are healthy foods that contains saturated fat

Saturated fats are also important for maintaining testosterone concentration

  • Testosterone is important to the athlete for building mass and strength

Tran-saturated Fat

Athletes should avoid trans fats.

  • Trans fats promote heart disease, diabetes, certain cancers and diabetes

  • Trans fats raise LDL (bad cholesterol) and lower HDL (good cholesterol)

  • Trans fats may also encourage muscle breakdown

Unsaturated Fats

Unsaturated fats are liquid at room temperature, and are considered beneficial fats because they can:

  • Improve blood cholesterol levels

  • Ease Inflammation

  • Stabilize heart rhythms

Omega-3’s are an important PUF as the body can’t make these, and they have been shown to have numerous health benefits.


Carbohydrates, just like fats and protein have provided much topic of discussion over the last few years, with people trying high carb diets, low carb diets and everything in between. The most important factor to understand is:

"Carbohydrate intake must be altered depending on the lifestyle and activities of the individual"

For an individual participating in lot of long duration and high intensity sport/exercise carbohydrates will be required in the body as they are the primary source of energy for the body and can be broken down in to ATP significantly faster than fats or protein.

However, for those leading reasonably sedentary lives, with a non-physical job and participating in minimal exercise (particularly high-intensity) then carbohydrate needs will be massively reduced, as fat can be oxidized and used as fuel. In another article I will cover the needs of the human being in caloric content in greater detail. What is most important when it comes to carbohydrate, is the form of carbohydrate we are putting in to our body.

What actually are carbohydrates?

Carbohydrates receive their name, because at the chemical level they contain carbon, hydrogen and oxygen. Carbohydrates are the sugars, starches and fibers found in fruits, grains, vegetables, milk products and also many processed foods.

Carbohydrates, like fats have to be broken down into component parts before being usable in the body to provide energy. Carbohydrates are broken down into glucose which can be used in the chemical reactions to produce ATP

There are 3 main types of carbohydrates available in foods:

1) Simple Starchy Carbohydrates (Sugar, Honey, Fruit, Fruit Juice)Have simple molecular structure and are made up of 1 or 2 sugar molecules

Simple sugars found in foods include:

  • Sucrose (table sugar, fizzy drinks, syrups, candy)

  • Fructose (found in fruit)

  • Lactose (found in milk)

Not all simple carbs are bad, natural simple carbs found in fruit and milk are perfectly healthy, but are best after training. However, the consumption of fizzy drinks, sweets, cereal bars, cereals need to be avoided like the plague. Consuming too much refined sugar has numerous associated health risks including:

  • Tooth Decay

  • Liver disease

  • Cancer

  • Weight gain and obesity

  • Chronic inflammation & immune dysfunction

2. Complex Starchy Carbohydrates

Made up of more sugar molecules combined together and include:

  • Whole grains, Peas & Beans

  • Due to greater molecular complexity these foods take longer to break down (less of an insulin spike)

All the above are good for the body as they are rich in energy, vitamins, minerals and fiber.

PROBLEM: Often complex starch carbs are refined (machinery has been used to remove high fibre parts from the grain)

Examples = white bread, rice, flour, pasta, sugary cereal

3. Complex Fibrous Carbohydrates

  • Fibrous carbs are rich sources of vitamins, mineral, phytochemical & antioxidants

  • Main source = GREEN vegetables

  • High fiber content means the food by-passes the gut and is essential for maintaining a healthily running digestive systems.


  • Asparagus, Aubergine, Green Beans, Broccoli

  • Brussel Sprouts, Carrots, Cucumber, Lettuce

  • Mushrooms, Spinach, Red/Green Pepper

Fiber is essential to digestion. Fibers promote healthy bowel movements and decrease the risk of chronic diseases such as coronary heart disease and diabetes, according to the U.S. Department of Agriculture.

One important thing to look out for when picking your carbohydrate rich foods at the supermarket is the ratio of carbohydrate:fiber, the closer the ratio the better. Generally, at a very minimum try and stick to 10:1 rule with every 10 grams of carbohydrate containing 1 gram of fiber.

Carbohydrate: Energy Release

  • Glycaemic Index (GI) = Rate at which carbohydrate in food is broken down into glucose and absorbed from the gut into the blood.

  • High GI = Quick release, causing spike in blood glucose level

  • Low GI = More gradual release, with less dramatic spike in blood glucose

  • Most of carbohydrate income should be in the form of LOW GI, however high GI carbs can be beneficial post exercise to rapidly replenish energy levels and stimulate plasma insulin creating anabolic environment.


Last but definitely not least of the macro's, and quite possibly one that has received the most attention in recent years, particularly in the world of strength training. Before talking about amounts of protein needed and reaching for powders and asking where vegetarians get their protein from, we must have a look at what protein is and its role within the body. Proteins are a combination of small compounds called amino acids which will always contain a nitrogen atom. This is important to note as nitrogen is a highly important chemical element that is essential for all life. A nitrogen shortage is associated with burns, muscle wasting diseases and serious injuries, whereas a positive nitrogen balance is evident in times of growth and tissue repair.

Before learning a little more about these amino acids lets get to know our friend protein a little better. Protein constitutes approximately 15% of the human body weight and forms essential components of all body tissues and structures:

  • Cell structure and genetic material

  • Metabolic systems (blood hormones, antibodies, enzymes)

  • Decrease muscle catabolism

  • Promote muscle recovery/maintenance

So amino acids are the building blocks upon which proteins are made. So when we consume food, the protein content in it has to be broken down into its amino acids that can then be used by the body for protein synthesis and muscle repair.

Whilst there are hundreds of amino acids there are only 22 amino acids in that can be used by the human body. Only 9 of these are classified as EAA’s (essential amino acids) as the body does not produce them by itself. Therefore, it is essential we are getting adequate amounts of these amino acids through the food we consume.

As always is the case "quality over quantity" (unless we're feeling like The Rock on a cheat day), the quality of protein is dictated by its amino acid content. Protein can actually be divided into complete and incomplete proteins

Complete = Contain all the essential amino acids

Incomplete = Missing one or more of the essential amino acids.

SOOOOOOO……… What are the essential amino acids you ask?


Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine

Non Essential

Alanine, Arginine, Aspartic Acid, Cysteine, Gluatamic Acid, Glutamine, Glycine, Proline, Serin, Tyrosine


1. Carboyhdrates and fats are our main source of energy

2. Protein is used for muscle repair, growth and metabolic actions

3. Aim to eat a good balance of carbohydrates, fats and protein from natural sources.

4. Vary your diet depending on physical activity and sport

5. Aim for a dietary macronutrient intake of 40:30:30 (carbs, fats, protein)

6. Avoid Trans-saturated fats and processed foods!

7. Build your own menu of meals and snacks you enjoy and that provide you with nutrition you need.

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