Macronutrients

 

The macronutrients are the body's fundamental nutrients. Macro, meaning large, means we need large quantities of these things on a daily basis compared to our micronutrients which we need much smaller amounts of. The three macronutrients are carbohydrates, fats and protein and they are all essential to our diet - we need to eat ALL of them for our bodies to function properly! There are many arguments out there over what the perfect macro ratio is, but the short answer is, eat enough of each of them and you will be doing just fine. 

 

Carbohydrate

 
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Function

Carbohydrates are our body's main source of energy. They are broken down in to single glucose molecules which the body either burns or stores in the muscles and liver for later use. Our brain runs mostly on glucose so it essential we get enough carbs in our diet. Carbohydrates do not make you fat - excess that your body is not burning will be turned to fat, but your body needs a lot more carbohydrates than you may convince yourself it does

Types:

Sugars: These are the smallest, simplest carbohydrate units. Any carbohydrate that is digested is eventually broken down to simple sugars - glucose, fructose and galactose and used for energy.

Starches: Although we don't associate starches with sweet sugars, starches are just very long chains of sugar. They are broken down to simple sugars and so that's right - bread and pasta end up being the exact same molecule as glucose in maple syrup.

Fibre: Any carbohydrates that our body cannot digest enter our large intestine and are called fibre - they are fermented by the bacteria in our gut for energy and have many beneficial effects for both us and the bacteria that we rely on. 

Guidelines

Total carbohydrate: 50% of energy - around 1000 kcal a day from carbohydrates

Fibre: 30g per day - 2 slices of brown bread has around 5g

Free sugars: less than 5% of energy (around 30g/day) - 1 250ml bottle of innocent smoothie

 

Fat

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Function

Fats, or lipids as they are called once they are in the body, are the most energy dense of the three macronutrients. While these sometimes seem less essential than carbohydrates or protein, they are very important. Every cell in our body has a membrane made of lipids and they also play important roles as messengers and energy storage. Some fat is necessary on the human body to cushion our organs and provide some insulation! 

Types

Saturated: Often seen as the big bad wolf of the fat world, high intakes of saturated fats are undeniably related to heart disease. However that does not mean we shouldn't have them in our diet, our body still needs some for normal function! Saturated fats are usually solid at room temperature: butter, lard, coconut oil.

Monounsaturated: The inbetweeners, monounsaturates are also great for our health, but perform slightly less compared to the polyunsaturates. These are liquid at room temperature and are in things such as olive oil, avocados and nuts. 

Polyunsaturated: The kings of the fat world, polyunsaturates do amazing things throughout our body and lower the risk of many diseases. These are our essential fatty acids: the omega-6s and omega-3s that everyone raves about for good reason. Liquid at room temperature, these are found in fish, seeds, nuts and some oils. 

Guidelines

Saturated fat: less than 11% of your energy intake 

  Women: less than 20g per day - around 4 sausages

  Men: less than 30g per day - around 4 sausages and 4 slices of garlic bread

Total fat: 35% of energy intake

  Women: 70g per day

  Men: 95g per day

Polyunsaturates: Aim for 2 portions of fish per week, one of them oily (salmon, mackerel, tuna)

 

Protein

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Function

Protein is our body's building material, we break it down in to amino acids which function as our building blocks. We use it to lay down muscle, create hormones, make structural tissues and make many other molecules that are vital for normal function. While we can use protein for energy, this is not what our body prefers to do as it is essentially the body breaking itself down. Think of protein as the wood that your house is built out of, if you have lots of wood you can make your house bigger and stronger, but if you do not have enough energy coming in, you may have to burn it to keep your house warm. We don't want to be burning our wood! Therefore we must eat enough protein to meet our body's requirement alongside enough of the other two macronutrients.

Types

Animal: Animal sources of protein are technically the superior source of protein - they can be digested and used much easier by our body (90-99% digested). They also are a richer source of all the amino acids, that is, they contain a greater variety. This means we are more likely to be getting enough of each amino acid from animal sources.

Plant: Plant sources are more difficult for our body to digest and use (70-90%) and tend to not contain as many amino acids. However, this does not mean plants aren't a great source of protein - if you are eating a variety of plant sources you will still be getting all of your amino acids. Additionally, soy is a complete source of plant protein - it contains all the amino acids our body needs!

Guidelines

Normal men and women: 0.75 g per kg of body weight per day

  80kg man: 60g per day - around 1 chicken breast and 3 eggs

  60kg woman: 45 g per day - around 1 chicken breast and 1 egg

Active individuals who are exercising fairly heavily: 1.2-1.5 g per kg of body weight per day

  80kg man: 96-120g per day - 3 chicken breasts

  60kg woman: 72-90g per day - around 2 chicken breasts and 2 eggs