As we know, our bodies (and our souls) require food to function as a mighty well-oiled machine. But what actually happens, when food is rapidly falling into your stomach, and all the pleasure of taste disappears like a sweet dream? We will dive into the science (just a little!) and meet with a calorie. This journey will help us to understand, how energy works to make our bodies live and move. And also it will shed light, why we usually can’t lose weight despite all these cruel burpees and a great number of tried diets. Let’s go!
A calorie story
You meet this word every day. Every product package in a supermarket has a nutritional facts table with a number of calories on its backside. And maybe you automatically scan it to decide, whether or not to include something in your diet plan. But what does this actually mean?
A calorie (cal) is a measurement unit, which was invented to convert insufferably delicious pancakes, a protein-packed chicken fillet or a cup of coffee into abstract units of energy.
The basic formula states, that 1 calorie equals the amount of heat needed to raise the temperature of 1 gram of water from 0 to 1 degree Celsius. But we used to measure weight in kg – that’s why a determination of kilocalorie (kcal), seems more familiar. 1 kg contains 1000 g, thus a kilocalorie is a unit of energy, raising the temperature of 1 kilogram of water (but if a poundcalorie had been existing, it definitely would have been much more convenient for some of us).
Ok, you could say, all the things above are good and possibly very significant for specialists, but how is it connected to my wish to lose weight? The answer is – energy.
Energy and nutritional value
Have you ever noticed that various food affects your mood and activity in dramatically opposite ways? Do you feel the same fullness 2-3 hours after eating a bag of potato chips in comparison with a good steak? If you do, you have already come closer to the concept of the nutritional value of basic “bricks” of life – macronutrients, known as proteins, fats, and carbohydrates.
Thanks to some enthusiasts, loved to burn everything they could get (in the name of science, of course), we know, that 1 gram of proteins, as well as 1 gram of carbohydrates, can give us 4 kcal of pure energy, while 1 gram of fats doubles the bet and releases almost 9 kcal. But they are not equal in terms of the Thermic Effect of Food. Now try to look at your favorite ice-cream not only as at a tasty treatment for your soul but also as at Pandora’s box with an enormous quantity of energy inside. And all you need to do is just release this genie out from a magical lamp. From the moment you are doing this, the game of balancing is starting.
1 g of proteins and 1 g of carbohydrates equally give us 4 kcal of energy, while 1 g of fats – 9 kcal. But they are not equal when it comes to digestion and extraction of energy
Since a calorie is a unit of thermal energy, it also obeys the first law of thermodynamics and the conserving energy law. One explains, how we basically spend our energy resources, while another one can give an answer on a question, making every dieting person suffering – “why I can’t lose weight?”.
What is the first law of thermodynamics and what it means for us, constantly seeking for a scheme of keeping our weight at bay? It describes how thermal energy is converted to and from its other forms and how it affects a considered system (in our case – human body). This law is inseparably connected with the conserving energy law, stating that energy cannot be created or destroyed. Everything it can do is just “morphing” from one form into another one. And that starts to seem familiar when we get back to our sophisticated relationships between food and weight.
If to imagine a human body as a car, and food as fuel, every piece of food can be transformed into an abstract quantity of gasoline, incoming to a gas tank (dinner time!). Some drivers prefer to purchase the fuel “by portions” just for one ride. In ideal conditions of a good road surface, nice weather and “fresh” condition of the vehicle, the car will probably have reached the desired destination, and some fuel will remain to be used for riding to the next gas station.
But there is another drivers’ type, which has a habit to fill a gas tank on “full”. In this way, if the distance is quite short and all the conditions are satisfactory, the car will burn not all the fuel filled in. This means that the remaining gasoline converts into deposited energy instead of an active one, waiting to be used again when need. And this is how it works in the real world: our bodies are not so different in this respect. If we consume more energy than we need to perform activities (and “passivities” too), all our excessive energy will be converted immediately. The body creates a resource to address to if, for some reason, you require energy and cannot get it in time. In other words, it creates fat stores to support you during possible dark times.
Evolution against your wish to lose weight
But don’t blame it for the bad behavior, reminding of some nervous persons which are always prepping for the end of the world or zombie apocalypse and stuffing their basements with kilotons of Campbell’s soup cans. Throughout its history, humanity had been surviving and overcoming circumstances and conditions, which had been being not so friendly: hunting could not guarantee the successful result, danger was expecting behind every bush, and extinction was not just a scary word.
Constant stress and uncertainty taught humanity to be prepared for hunger. That is why every particle of energy, came with food, must be used or deposited. Can you imagine a medieval peasant, dreaming to lose weight?
Only for the last 100 years, the circumstances became different. For the developed countries, now there is not a single sign of hunger. The food industry produces very “cheap” calories in amazing quantities, which are available for almost everybody. And now, despite the fact we understand our “safety” in questions of food plentitude, we still live our lives as cavemen, because our brain can’t change so quickly as our environment does. And instead of searching for any accessible “fuel” to survive, now we need to turn our behavior patterns against our nature and start controlling everything we consume. Because every excessive unit of energy is a potential candidate to be conserved in our fat depots.
“How can I control so primary instincts? I will never lose weight!” – you can say. Good news – you definitely can! And, moreover, in two separate ways! One way is to control your nutrition, and another one is raising your activity levels during a day.
Energy: the expending and controlling ways
Body’s energy requirements
We can expend the energy we have got out of food or our inner fat storage in several ways. Approximately 70% of energy is spent on the basic needs of a body such as the renewal of tissues of your organs, breathing or blood circulation – this rate is called Basic Metabolic Rate or BMR . Another 15-20% goes to serve your everyday non-exercise activities (NEAT), whether it is a typing of a message or cleaning a house. Releasing the energy from consumed food during digestion takes an additional 10% (this is called the Thermic Effect of Food or TEF), and only 5% of the remains is expended on exercise activities.
Surprisingly, but, despite the widespread myth telling us that we must totally “waste” ourselves in a gym to make numbers on our scales move in the right direction, the energy spent on this type of activity is poor in comparison with non-exercise activity or energy we require to maintain our bodies’ basic functions.
Non-exercise VS exercise activity
So, the good news is you don’t need to die in the name of the better shape. Just start a good practice of walking instead of using a car to go shopping or play with your pet more frequently. But in addition to that, it is still highly useful to grow muscle mass, because this is one of the best ways to increase your total energy expenditure during a day.
Muscles are the most active consumers of energy, and if you have a good muscle mass, it promises you to be more fit (and to lose weight faster). A lot of professional bodybuilders and athletes can brag with their crazy diets, containing 10,000 kcal a day in comparison with an average 2,000 kcal for women and 2,500 kcal for men, recommended by USDA. But besides the muscle story, they are also extremely active people, because the sport is their profession, so for the most of us, this awesome kcal quantity is just an unnecessary addition to belly fat.
In terms of spending energy, it is much more effective to add some more activity to your life. Why don’t you try to dance, while cleaning a house?
Speaking of average kcal requirements, it is important to stress, that they were deduced for understanding, how much an average person consumes to maintain a stable weight. And for every one of us, this rate will be different. For getting the most accurate knowledge, you can use the modern Mifflin St. Jeor equation formula to understand your Basic Metabolic Rate (serving your needs in the condition of absolute rest) and add an activity index, based on your lifestyle. Try it out to get a result!
Armed with this knowledge, now you can start counting, how many kcals you can consume to successfully operate with the numbers on your scale and how much energy do you really need to live the life you always wanted to. If you want to lose weight, you don’t need to kill your taste buds and mood with help of a terrible mono-diet or give your valuable lifetime, performing those countless jumping jacks. Just consume a little bit less to push your body to use its own stored energy from fat. If you want to gain weight, just eat a little bit more, and your body will get the idea.
The answer is simple – find your own balance, and feel great every day, when you wake up and realize, how effective and smart your body is. And finally, allow yourself that small piece of pizza. You will find a way to spend it’s energy a little bit later.
- Hall, Kevin D et al. “Energy balance and its components: implications for body weight regulation.” The American journal of clinical nutrition vol. 95,4 (2012): 989-94. doi:10.3945/ajcn.112.036350
- Müller, M., Geisler, C. From the past to future: from energy expenditure to energy intake to energy expenditure. Eur J Clin Nutr 71, 358–364 (2017). https://doi.org/10.1038/ejcn.2016.231
- Trexler, Eric & Smith-Ryan, Abbie & Norton, Layne. (2014). Metabolic adaptation to weight loss: Implications for the athlete. Journal of the International Society of Sports Nutrition. 11. 7. 10.1186/1550-2783-11-7.
- U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2015 – 2020 Dietary Guidelines for Americans. 8th Edition. December 2015.
- J.M.K.C. Donev et al. (2018). Energy Education – First law of thermodynamics [Online]
- J.M.K.C. Donev et al. (2018). Energy Education – Law of conservation of energy [Online]