Calories are a Myth: Why Thermodynamics and Diet Don’t Mix

Ladies and gentlemen, are you ready for today’s hot take? When “experts” start throwing thermodynamics into discussions about calories, I can’t help but wonder: Did everyone just snooze through high school science? Or are we all collectively part of an inside joke I didn’t get the memo for?

Let’s dive in before someone accuses me of hating on science (I don’t – I swear I love my lab coat).

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Calories: The Greatest Hoax Since Low-Fat Cookies

Here’s the problem with the almighty calorie: It sounds scientific. The word drops into conversation, and suddenly everyone’s nodding their heads as if we’ve all secretly passed Tests in Advanced Physics. But here’s what most people don’t know – the thermodynamics that these “calories in, calories out” folks cite relies on the principles of closed systems.

Yes. Closed systems. Now you might wonder, “What’s a closed system?” It’s something isolated, where energy flows don’t interact with external stuff – no air, no gossipy co-workers, nothing gets in or out. Think of those old chemistry lab experiments with sealed flasks. Fun science, sure. But here’s the kicker: humans are not closed systems. We’re open systems – dynamic, messy, and a little unpredictable. We’re breathing, sweating, excreting, living creatures. Good luck cramming that into a tidy calorie equation!

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Thermodynamics for Dinner: A Crash Course

Let’s crunch the numbers using thermodynamics (cue dramatic music). The equation physicists and nutritionists may throw around like it’s gospel is:

ΔU = Q – W

Stay with me! It’s not that scary.

• ΔU is the change in internal energy of a system (AKA your body in our context).

• Q is heat added to the system (energy intake, a.k.a. your food).

• W is mechanical work done by the system (like exercising or pacing angrily).

Sounds neat, right? But the human body doesn’t just “absorb food as heat” the same way a kettle heats up water. Digestion is complex, involving countless enzymes, hormones, and bacteria that determine how food is used versus stored. The efficiency of this process depends on your metabolic rate, hormone levels, gut health, and yes, even your stress levels. Stick that in your thermodynamics equation, I dare you.

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Why Mass (Not Calories) Matters

Now let’s talk mass. Food isn’t just some number you convert into energy during digestion, it’s a physical substance. Its weight, composition, volume, and even its water content determine its impact on your body. For example:

• A 300-’calorie’ bowl of oatmeal ≠ A 300-’calorie’ steak. Why? Macronutrients and fiber content (or lack of) ensure your body processes them differently.

• High-water-content food (e.g., watermelon) weighs more but is less ‘energy’-dense, filling you up faster without nearly as much ‘energy’.

• Mass impacts how much food stretches your stomach, which in turn signals fullness via hormones like leptin.

  

The ‘calorie’-counting narrative ignores these distinctions entirely. And don't get me started on what happens when food’s thermic effect (e.g., how much energy it takes to digest) enters the mix.

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Why the Experts are Wrong About Thermodynamics

When nutritionists or fitness “gurus” wave thermodynamics around like holy scripture, they miss one glaring detail: human biology doesn’t operate like the simplified systems seen in physics textbooks. In other words, they’re doing that thing kids do where they stuff triangles into square holes because hey, shapes are shapes.

So, yes, technically thermodynamics underpins everything in the universe. But applying it to human diets without understanding open systems, adaptive metabolisms, or the psychological aspect of eating (stress-eating that chocolate bar at midnight, anyone?) is completely off the mark.

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Humans: Glorious Open Systems

We’re intricate, energy-flowing machines. Sure, we obey the laws of physics, but we're full of exceptions and nuance. Just as a photon of light has no mass but great energy, the way we process food depends entirely on context – our unique hormonal setup, microbiomes, lifestyles, and activities, not to mention interactions with our environment.

What this means is: focusing on the mass of food, not calories, gets us closer to the truth. It reflects the tangible, physiological dynamics that occur in our bodies, rather than relying on artificial numbers pinned to outdated calorie theories.

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Conclusion: Calories, You’re Cancelled

Here’s the deal: people eat food, not equations. We are gloriously complex, ever-changing, open systems governed by a symphony of processes. So next time someone gives you a lecture on thermodynamics and how your fatty steak “cost” you 250 calories, ask them if they’ve calculated the heat loss from your constant eye-rolling.

Don’t let calorie counters fool you – the truth is too big, too dynamic, and frankly too scientifically fascinating for their outdated math. Eat the mass of real food and skip the math equations at dinner.

Now, where’s my steak and eggs? For science, of course.