The law of thermodynamics is an actual law of science.
It's actually a unifying principle, meaning it's always true in the universe.
Wait there's more than one?
The universe being the boundaries of the thermodynamic system. Now a common misunderstanding is that people think it's "the law of thermodynamics," meaning one law. It is not. It is actually the LAWS of thermodynamics, there are more than one law. So the laws of thermodynamics are scientific laws of physics. This is the first hole in the calories argument. They don't know what the laws are!
I don't even know who this "they" is I am speaking of, it's like any great urban legend or story. You don't know who first started it, just that now everyone believes it and has their own version of it. Like people think penguins mate for life, they don't. We also think the first super continent was Pangaea. It wasn't, it was Vaalbara. We think think there is only one law of thermodynamics, and its all about weight gain or loss. It's not, its about everything.
Why am I talking about this? Because it's often used in fitness, specifically in talking about your weight. So being a scientific principle, is it physicists talking about this in relation to health? No. Chemists at least? No. Just the typical meatheads and hippies who teach everyone about health, fitness, and wellness.
Am I a physicist? No. Neither is a doctor or the president. But I have always been a smart ass who's had a lifelong interest in science (and I have a world famous physicist as a client so that helps as well).
So what the hell have people been talking about all these years with the law of thermodynamics? They are actually (at least I think anyway, I have a hunch it was a scientific analogy that went awry) just talking about the first law of thermodynamics. The conservation of energy law. Meaning energy cannot ever be create or destroyed, just transferred. This is a real legit scientific law.
The law of calories is not a scientific law
Even though many industries and people want it to be (and need it to be). Physicists probably don't care enough about this to spend any actual time debunking this. If it was, a lot of people's careers would be over, and a lot of empires would crumble.
So DO NOT confuse this pseudo health idea of calories in and out vs the first law of thermodynamics.
It's when you have to use mental gymnastics to apply this principle to diet is when it starts to unravel.
Why not conservation of mass?
First of all, food is matter. So why aren't we using the law of conservation of mass? Because matter (the building block of mass) is not perfectly conserved. A particular difficulty with the idea of conservation of "matter" is that "matter" is not a well-defined word scientifically.
But even when matter is not conserved, the mass and energy associated with matter are conserved. So the second best thing, let's go back to the conservation of energy principle to explain weight gain (or loss). First of all you can't pick and choose laws of physics, secondly this idea of matter not being conserved is an important thought that I'll come back to later.
How do we even know how many calories are in things?
The first fallacy is the assumption that we have a perfect system to determine calories in the first place. We don't and that's one of the fallacies in the laws of rational debate. Told you I was a smart ass.
How do we determine calories?
Over a 100 years ago, agricultural chemist Wilbur O. Atwater literally burned food in a device called the bomb calorimeter. It's basically a fireproof container sheathed in water and hooked up to a thermometer. He used it, along with a larger device capable of measuring the heat output of an active person, to figure out how much usable energy different foods possess. His conversion factors are still used today. He started all this mess.
The idea is that burning food shows the total energy that it contains, but it doesn't account for what the human body cannot absorb, nor what is used in the digestive process. So Atwater derived a set of tables that specify the practical energy values of different foods, distinguishing, for example, among different sources of protein. The most recent update to the conversion tables was published by the U.S. Department of Agriculture in 1973...
Anyone else see problems here? And food companies themselves do their own labeling and calorie quantifying.
Lots of room for error here.
Multiple Energy Pathways
Even in the conservation of energy, there is leakage. Meaning there is energy lost in inefficiencies. It still exists and was transferred somewhere, just hard to measure where exactly, could be the cost of conversion to seepage somewhere in the closed system, etc. Now none of this applies unless its in a closed system. Are we a closed system? Not really, we fart, burp, poop, pee, bleed, etc. But you still want to believe, so let's keep at this.
Food first of all is matter. Matter is not perfectly conserved, and in conversion to energy, it also loses something.
Here is the other thing, even though the energy is conserved by being transferred, it is not just transferred to one thing. There are multiple energy pathways. It's not all turned into weight. Some of it gets used right away, there is the actual thermic cost of ingestion, some of it gets stored as fat, some of it gets crapped out, some of it turns into gas, some of it stored as fat, some of it converted to muscle, some of it chemical energy, some feeds bacteria, mitochondrial energy, and then there is also the cost of conversion, and many other pathways for energy to be transferred (in and out of our bodies). Maybe some of the energy flew out of your mouth because you were chewing with your mouth open.
This also assumes the actual caloric measurements of your food was accurate in the first place.
Different things transfer energy differently
Let's say you had a brick and a rubber ball. Both weighing exactly the same, both falling to the ground at the same speed and from the same height. What happens?
The total amount of energy in this experiment is the same. How the energy was transferred is completely different.
The rubber ball bounces off the ground, the energy meets the ground, creating ground reaction force, the ground absorbs some of the energy but a lot of the energy goes back into the ball and the ball bounces. On the drop of course air also stole some of the energy, not to mention inefficiencies.
With the brick, the energy was different. It did not react back up, the energy exploded all over the ground.
Different things disperse energy differently. Do you absorb calories the same way when you are healthy as when you are sick? What about time of day, what about before or after work outs or other states? What about a muscular person vs a fat person? What about your friend who never gains weight no matter how much they eat and they don't even work out? And your other friend who gains weight just thinking about food.
We can agree based on the person, the reaction to calories and where the energy goes is different.
Source of energy
So why isn't the same true for food? Meaning the source of the calories. Wouldn't different foods make energy get transferred in different ways? Like something with a lot of fiber, or something really spicy that makes you run to the bathroom. Or something gross that makes you throw up. Energy was dispersed all very differently. Or you ate something you are allergic to. Lots of room for error.
You know when you see someone eat a lot and you have to ask,
"Where does it all go?"
Because they never gain any weight. But that's a good thought, where does it all go, because the calories are not being absorbed. This person is displacing it differently. Check the toilet, they may have irritable bowels.
Does protein react differently from carbs? Do fats react differently than sugar? Energy will be transferred somewhere but different sources of energy will create different displacement of energy. Calories matter, but it's not the only thing that matters. A real life case study would be all the calorie counters of the 80s. They would be skinny if calories were the only thing that mattered and all calories transferred energy all in the same pathways at the same percentages, and for everyone exactly the same way.
Consider for example a sponge. If your poured a liter of water over a 5oz sponge, it would absorb a certain percentage of the water, and some of it would be lost. Now you poured onto it a liter of sand. We can safely say even less of it would be absorbed and the majority of it lost.
This is the true first law of thermodynamics
Is it starting to make sense? All the energy is accounted for, it was not destroyed, it's still there in the universe. It's just not in the sponge. Scientific laws are not that simple to interpret, 100% of the calories you ingest will not be absorbed by you, and based on what kind of foods you eat, the distribution of how much and where it gets absorbed changes. Thinking it's all still inside you or that it all went to fat is NOT the law of conservation of energy. It is the stupid health law of calories.
Don't even get me started on cleanses and the belief you can flush stuff out. Its like the reverse of this idea, that it all goes in and a cleanse gets it all out...
Type of energy matters
Still don't believe me? Because calorie counting is popular belief, and popular belief is fact right? Don't people think if you lift weights you also gain weight? And 1lb of muscle weighs more than 1lb of fat? Wait myths are also popular belief. Science doesn't care if its popular belief or not to be true.
So imagine you have a bowl, and you are trying to collect liquid water and you then try to collect steam. The same amount of water and steam is released. Which will you be able to catch more of? Water or steam? The same amount of energy (matter really) was released. But steam harder to collect than liquid.
So then would fruit juice absorb differently than eating and chewing the actual fruit? Another popular belief, that juices are better than eating the real thing. What about cooked vs raw?
Here is another unifying principle that all scientists know. Variables actually matter! YOU CAN'T IGNORE THEM. Everything matters, that's how the universe works.
Speed of energy
So here is my next point. What about the speed of energy. Meaning let's say you had a leaky cup (because that's what we do, we leak, go check your bathroom) and you are collecting water from a faucet. If 1 gallon of water came pouring out, would you be able to fill your leaky cup? Probably. What if 1 gallon of water trickled out. Would you be able to fill your cup? Probably not, you may even have a hard time trying to keep it from going empty.
So the speed of calories hitting your system matters. If you drank it or ate it quickly, would it be in your system quicker than solid foods or slow chewing? Yes.
If you ate 100 calories of protein and 100 calories of sugar, would the speed of energy be different? Yes. Which would spike your blood sugar quicker? Sugar. So does food high in the glycemic index (foods that cause a rapid blood sugar spike) affect your weight loss differently than the foods low in the glycemic index? Sugar, starches, refined carbs absorb quicker than everything else. That matters if your goal is not gaining more weight.
If you have a bad ankle and stepped onto a curb, it probably wouldn't hurt your ankle. It would distributed onto the ground, some on your shoe, some your ankle, your knee, your femur, hip, and up the kinetic chain.
Let's add speed. If you jumped off the curb onto your bad ankle what would happen? All the energy would be conserved on your injured ankle (this is actually a great example of how injuries work, it's the inability to distribute the energy up the kinetic chain, this is a better way to use the law of conservation of energy but that's a whole different article).
So what happens? Your ankle explodes. Energy was not distributed properly. Instead of multiple pathways, it was mostly absorbed in one area. Whereas when you were doing it slowly, it was distributed better.
Survival of the most efficient (fittest)
Our bodies are very efficient, we try to do things that cost the least. Having your ankle explode would cost our body less energy than trying to disperse that energy. Storing something like sugar into fat is more efficient than trying to do something with all of that energy very quickly when all you are doing there is sitting. Our bodies are amazing, we rule the planet because we are efficient.
Why does my back always hurt? Why does my knee always hurt? Because they are strong places that are in the middle of your torso and your lower body. They can take a lot of damage. So its easier for your body to have them just do most of the work than try to get your whole body to work as an organism. That would actually take strength, and because most of us are no longer strong, we rely on our strongest areas to carry the load. So your body chooses back pain than you falling over and dying.
We are efficient and our bodies will always do whatever is easiest for it to do, to try to keep us alive for as long as it can. Whether you are in pain or not during that process is a different matter.
Even our genes are efficient. We have thrifty genes, it can run and survive on very little food. It can even figure out how to store fat on very little food.
Now is that effective still in the modern world? But it used to be. Our food is just changing faster than we can, we outpaced food in evolution at one point, now we are exponentially evolving food faster than us.
Simply cut a few calories
"Most of us have learned that if we just cut our calories by 100 calories a day, or increase our exercise a little bit over the long haul, we will lose weight. It’s all about the calories in or the calories out.
Sorry Mr. Newton, your laws of thermodynamics don’t apply in living systems. Biology and metabolism are more complex. If we just go with the math and burn an extra 100 calories a day by walking one mile or consume 100 calories less in 35 days, you would lose one pound (3500 calories = 1 pound).
And over five years you would lose 50 pounds. Yet, in studies they find you would lose only 10 pounds in five years. This occurs because of changes in your metabolism and calorie needs as you lose weight." - Dr Mark Hyman
But calories matter
I have to keep saying that because if I don't some people will get mad at me. If you had an army, think of calories as the guns. Having more guns matter. Is it the only thing that matters? No. What if they can't aim. Now what's more important, total guns or accurate aim? It's unclear.
A smaller army with less guns and better aim can out do a bigger army with poor aim. Not always but it can. Now what happens when you have a large army, lots of guns, with really good aim?
That's basically the modern diet. Lots of foods that absorbs quickly, that we eat too fast, too often, and we wash it all down with liquid food. And we are getting sick, and majority of the illnesses are inflammatory. What's inflammatory? Foods that are high in the glycemic index...
I'm sorry but science is complex
Calories matter but it's nowhere as simple as calories in, calories out and reducing complex scientific ideas to slogans doesn't help the cause of educating the public.
This idea preys on the lack of scientific knowledge of the audience. Our job is to educate the public not manipulate them.
It's calories in calories out only when all other variables remain constant. Which is highly improbable.
You can't explain weight gain and weight loss purely with calories, there's more to it than that.
So in conclusion
Physicists don't argue over calories in and out. They know better. Just like they don't go online to argue over global warming like we do. Its basically people like me and other non-authorities in physics arguing over this stuff. And we don't know nothing.
So are you going to take physics lessons from a bunch of meatheads, trainers, and the government? I'm no scientist but that sounds like a bad idea.
Sam Yang from an early age has been obsessed with connecting the dots between martial arts and efficiency, health, mindset, business, science, and habits to improve optimal well-being. For more info, join his newsletter. You can also connect to All Out Effort on Facebook and Twitter.