ENERGY EXPENDITURE 1.0: UNDERSTANDING ENERGY
First thing’s first: Do you like lasagna? Yes, no, maybe. Yes? Okay, good. We’ll come back to that later. This is lasagna, by the way, and it is super yummy, has balanced macros and you can’t not like it. Hold that thought and we’ll talk more lasagna later.
In case you really don’t like lasagna (?). Here are some pancakes!
This is the first in a series of posts I have made increase your understanding of the basic and the not so basic elements of energy expenditure – How and how much your body uses energy everyday. The idea for this series came together after I realized that metabolism and how the body uses energy can be hard to understand for a lot of people, and because of that relating to energy intake a.a food, and the magnitude of food can be challenging. It can also be challenging to understand how exercise affects the need for more or less energy. This is not a blog post about dieting per se. It is about understanding the amazing machinery that is your body, that is you.
I am a firm believer that knowledge is power, and with all the feelings often attached to food and body image, I think increasing your knowledge about the works and ways of both food and body can help you make healthy choices for yourself and feel good about yourself. Also, when somebody asks you how your training works or why you are doing it this or that way, you know what to say. Less awkwardness all around, thank you very much.
I am Wikipedia’ing the heck out of the technical terms and names here, in case you want to check them quickly out while reading, and other references you’ll find at the bottom of the posts. Mind you, this one doe not have literature references, but please shout out if you need them and I’ll happily provide them.
Energy: Chama- chama- chama chameleon
Energy is a chameleon-like property of objects that can be transferred onto objects or converted into different forms. That means that energy can never disappear, it just takes on a new form. Depending on the context energy can be defined in different ways and there are different types of energy, for example: kinetic energy, elastic energy, potential energy etc.
We’ll deal with the type of energy that comes from your dinner plate and coverts to physical movement. In order for that to happen your lasagne or pancakes needs to be converted into chemical compounds. More specifically, it needs to be converted into a little bugger of a molecule called ATP, which is a chemical compound used as an energy carrier by the cells. ATP molecules caries energy where it is needed and when ATP breaks down energy is released. I will not hit your snooze butten and elaborate how ATP is made, but on a quick note it can be made in many ways and mainly by the following three pathways: the glycolysis, the citric acid cycle (also known as Krebs cycle) and the beta-oxidation (fat oxidation). Without ATP we don’t exist – yes, we die. ATP is essential for both movement and respiration. ATP is so vital and famous that is has songs made about it. This is an oldie, but a goodie that we used exam prepping back in the day. Whohooo!
But what type of energy can the lasagne and pancakes become?
We can also say that ENERGY is the ability of a system to do work. You are the one who is going to be doing the work, because I assume you will be doing some type of training that demands oxygen in the foreseeable future, so we are talking about mechanical work. Mechanical work is a term from physics, and work is related to energy. If you didn’t have physics in school this may all be a little “floating”, but if we give mechanical work a unit or two I think you will recognize and understand it better.
The unit for Work is Joule (J), which is a name you might have seen on food labels next to the more much famous, loved and hated: Calorie (Cal) or Kilogram Calorie (shortened kcal in Norwegian). The popular term, which I’ll be using as we go on is calories (cal). Both calories and Joule are units for energy:
1 Joule = ca 0.2.4 calories
1 calorie = ca 4.18 J
So calories are in fact not “tiny little creatures that sew your clothes tighter at night”, they are energy units and therefore we can look at calories in this way as well:
Both you and the light bulb need energy to function, but you obviously function in completely different ways. ATP and electricity is not the same. Duh! You need energy a bare minimum to energy just to biologically exist and this need for energy is determined by your basal metabolic rate, but how much you need every day on top of that all depends on your daily energy expenditure.
What determines your total daily energy expenditure?
The answer is A LOT of things:
- Termic effect of food: Converting food to energy will initially cost some energy. Cost of processing food and storing.
- Termic effect of exercise: The costs of moving your body.
- Non-exercise activity thermogenesis – NEAT: Everything from fidgeting to yard work.
- Resting metabolic rate, which in turn is affected by individual gender, body size, genetic predispositions, body composition (fat mass, fat free mass), hormonal and nervous system, medications and environmental temperature.
- Pregnancy, lactation
As you can see, apart from your resting metabolic rate, how much you move and the cost of those movements greatly influence your need for fuel. When you do a X type of movements, at Y intensity for Z amount of time your body will use different energy systems to get it’s chemical energy (ATP, or in some cases creatine phosphate, but we’ll get to that in another post). The Y intensity and the Z amount of time will to a lagre extent determine what type of energy source you are getting ATP from and at what rate, THIS really affects your caloric burn during training!
This is an example of a question I get asked a lot, almost every week:
“When you want to burn calories in general or fat specifically, is it better do do 7 minutes of HIT (high intensity training) or 40 minutes of zone 1 training?” We’ll se about that in the next Energy Expenditure post! I want you to understand the relationship between need for oxygen and caloric costs foh real!
Be seeing you!