I figured the perfect place to start would be with some of the basics of nutrition. So schools in session and we're starting from the top.
Energy. We need it. You know that. I know that. Where do we get energy from? Now there are all sorts of ways that people may feel energized; they may drink a cup of coffee, have a cold shower, exercise, meditate but at a physiological level there are only four different things that our body can use to produce energy. The name given to three of these things is MACRONUTRIENT. Said MAC-RO-NUTRIENT. These are sometimes referred to as macros. We get these from food.
The three macronutrients are:
I like to think a lot of you reading this would have heard about macronutrients before. For those that haven’t food is made up in varying amounts of these macronutrients. When we eat our body breaks these substances down through digestion into smaller forms of these nutrients where they then get absorbed. After absorption they enter our bloodstream where they are transported around our body. It is these substances that our body uses to make energy to allow us to do anything and everything. Though they may all provide us with energy there are some distinct differences between the three macronutrients.
Firstly, the amount of energy they provide is different. Energy is measured in kilojoules (kJ) or calories (kcal). Per gram, fat (also known as lipids) provides us with 9 calories or 37 kJ, whereas carbohydrate and protein provide us with 4 kilocalories or around 16-17 kJ per gram.
As well as providing us with energy these macronutrients also have other functions in our body. Fat is needed for hormone regulation, cell function and the absorption of fat-soluble vitamins and antioxidants. Protein is needed for muscle, skin, nail and hair maintenance and growth; proper functioning of our organs; immune function; hormones, enzymes and transport of substances within our blood. Carbohydrates are used to maintain our blood glucose or blood sugar levels and are normally where we get most of our energy from. Fiber is also a type a carbohydrate however our body doesn't break it down well; therefore it provides very minimal energy. Fiber is really important however for our gut health, keeping us regular and helping to keep us full.
In terms of storage in our body fat is stored as, well, fat. Carbohydrates are stored first in our muscle and liver as a substance called glycogen. As our glycogen stores start to fill up excess amounts of carbohydrate can also be stored as fat. Protein has no specific storage form so if it is not needed it can be converted either into a form of carbohydrate or fat/lipid.
There is one other substance that our body can use to derive energy and that is alcohol (ethanol). Alcohol provides us with 7 calories or 29 kJ per gram. However, it is not considered a macronutrient as we do not need it.
Now the purpose of this post was to give a brief overview of the macronutrients and explain where we get energy from. I also want to make one other point clear and perhaps this is the first thing I can remove some confusion around. No one macronutrient is inherently bad (alcohol is not recommended but this isn’t really a macronutrient). I will save the fat vs carbs discussion for another post but just know that specific macronutrients should not be demonized. You should eat fat, you should eat carbs and you should eat protein. The ratios in which we need these will be different from person to person, but everyone should be having some of each.
Thanks for reading.