Back to basics: Macronutrients explained

You may be wondering, 'What exactly are a macronutrients?'. Quite simply, they provide energy in the form of calories and make up the three major components of food – carbohydrates, fat and protein. Having a basic understanding of how these are used by the body can people make more informed decisions when working them into your daily food consumption.

The Nutrient Reference Values (NRVs) are a set of recommendations for nutritional intake for Australia and New Zealand, set by the government. From the NRVs, it is suggested that our diet is comprised of 45-65% from carbohydrates, 20-35% from fat and 10-35% from protein. Well where does alcohol fit into the picture? Alcohol intakes should be below 5% of dietary intake, thus there is NO recommended daily amount for this.

Lets break these down a little more.

Image via Pintrest

1. Carbohydrates

Once ingested, carbohydrates are broken down into a simple sugar called glucose. Glucose is the first / main energy source that our body will use for fuel so that we can function everyday. Our blood glucose (sugar) levels are regulated using a hormone called insulin, which by reduces blood glucose levels when these are too high and through another hormone called glucagon which increases the levels when they are too low.

It’s important you choose complex carbohydrates such as starchy veggies, fresh fruit, wholegrains, beans and lentils, as the energy from these foods are released over a longer period. Consumption of simple carbohydrates (chips, lollies, cakes, pastries, chocolate, soft drink and breakfast cereals) causes a rapid spike, followed by a quick drop in blood glucose levels which endorses a large drop in a person’s energy. Any excess glucose that isn’t used by the body is stored as fat – we will touch on this in a later post.

Note: Per 1 gram of carbohydrate is 16.7 kilojoules (kj).

2. Protein

Protein is comprised of 22 amino acids, which act as building blocks for our cells. 9 amino acids are can not be produced by the body, thus must be met through our diet. Protein builds, strengthens and repairs muscle tissue, makes antibodies for our immune system, produces hormones and enzymes and transports oxygen through the blood. Protein can not be stored in the body, thus is converted into glucose via a mechanism called gluconeogenis. Per 1 gram of protein is 16.7 kj, which is equivalent to the energy provided by carbohydrates.

Protein is found msot commonly in animal products such as red meat, fish, poultry, eggs, and dairy. Vegetarians and vegans are often at risk of inadequate protein consumption thus must combine plant based foods such as beans, legumes, quinoa and rice to obtain teh right sources of essential amino acids.

3. Fat

You wouldn't be human if at some point in time you believed that 'eating fat would make you fat'. Unfortunately, in the 1970's and 80's food manufacturers stripped all the fat from products such as yogurts, cheese, milk, biscuits etc and marketed these as 'low fat'. But something has to give right? You bet it does. If you compare the back of a full fat yoghurt with it's ''lite or low fat' version, the sugar content will be higher on the low fat one. That's right, they took the fat out and replaced it with sugar. Surely this correlates with the 63% of overweight and obese people in Australia during 2007/08?

We don't want to be eating every type of fat though; trans fat is a definite no no and saturated fat is a sometimes as they contribute to high cholesterol levels and poor heart health which can result in more profound health conditions such as cardiovascular disease, heart attacks and strokes. Saturated fats can be found in healthy foods such as animal

products (chicken, beef, lamb etc.) or plant foods (coconut oil, palm oil etc.) although considerably less than the amount found in fried or processed foods such as pizza, dairy, cakes or biscuits.

It is important that you are consuming plenty of mono or poly unsaturated fats found in foods such as extra virgin olive oil, seeds, nuts, avocado and oily fish (salmon), as they are needed to support cell growth, protect your organs, nutrient absorption and hormone production. It is often said that fat will keep us fuller for longer and for good reason as it is the most energy dense macronutrient with 36.7kj provided per gram. This is an additional 10kj per gram that what is provided by carbohydrate and protein. Unlike carbohydrates, fat does not have an effect on insulin so will have a negliagble / positive affect on our blood sugar level.

Finally, Omega-3 fats are an important type of polyunsaturated fat, which the body can't produce thus they must be consumed from food for inflammation and brain health.

One way to check the ratio of your macronutrients is to track them using a free application such as My Fitness Pal (MFP). You can download this onto your phone or access it online. The beauty of MFP is that it can paint an overall picture of your current eating and help you assess whether you're making the most optimal food choices for your health. It's funny, we always think we're eating less that what we really are.

Go one what are you waiting for, download the app now and try tracking for a few days.

You'll be suprized to see how much energy (kilojoules /calories) you consume across the day, where this energy is stemming from and any symptoms you may get from certain foods i.e. bloating, digestive issues, flatulence, constipation. I'm not here to tell you to cut out certain foods groups or eat a particular way, but sometimes a food diary can be vital when working out why some foods make us feel good and others not so great.

There you have it, a brief but kind of long overview of the macronutrients! If you have any specific questions or topics you'd like me to cover, please leave a comment below and I'll take a look.

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