A Tale of Two Caloric Deficits

Why "caloric deficit" thinking is Tautological and How to Think Better

What the author imagines he looks like battling CICO bots on Twitter.

A certain segment of people likes to say the words “CICO” or “deficit” a lot. They probably imagine that these words are related to science or something. I call them CICO bots. Living tissue over CICO endoskeletons.

The word deficit is, of course, an accounting term. Countries have budget deficits or current account deficits, and companies and households and people can have deficits or surpluses. It has little to do with science.

Now I love accounting as much as the next guy but I really don’t get how this is an discussion-ending argument.

Strictly speaking CICO is a tautology

CI (Calories In) - CO (Calories Out) = Deficit/Surplus

Yes, every calorie that enters a body must either leave the body or stay in the body. This is tautological.

Saying “somebody lost fat” is literally saying that calories left his body. This is not something that needs to be proven. It is the meaning of the statement.

It’s like saying somebody who got richer added more to his bank account than he spent. That is the definition of getting richer.

Testing this empirically only proves one point: you misunderstood the question.

As commonly used CICO is demonstrably false

What strict CICO does NOT mean are any of the following:

• Eating less will cause weight loss (not if ΔCI < ΔCO)

• Eating more will cause weight gain (not if ΔCI < ΔCO)

• Exercising more will cause weight loss (not if .. you get it)

• Exercising less will cause weight gain

• One person eating more than another will cause that person to gain more weight than the other (not if CIa - COa < CIb - COb)

CICO bots will usually perform this bait and switch countless times throughout a discussion. They will tout the tautology and when you point out that it doesn’t lead to any of these conclusions they counter with “Why do you HATE SCIENCE? Why do you hate the FIRST LAW OF THERMODYNAMICS?”

But they clearly haven’t done the math. It’s easily possible to solve these equations in ways that perfectly conform with the CICO accounting tautology.

I have personally invalidated all of these sleights of hand:

• I’ve stayed weight-stable for 2 months straight eating 1,000kcal/day

• I’ve over-eaten at an average of 4,200kcal/day for 30 days and lost several pounds

• I’ve harshly exercised (CrossFit for an average of 4.2x/wk over 1 year incl. sick/vacation time) and not lost any significant weight

• I’ve lost 100lbs without any exercise or restricting caloric intake at all

Of course these aren’t surprising. The CICO equation allows for all these possibilities because..

Calories In and Calories Out don’t stay Fixed

Here’s how these obviously happened:

• I restricted calories and my body turned down the metabolic rate to its minimum to conserve energy

• My body burned off all the excess energy in heat & activity

• My body just made me more hungry to compensate for the energy burned exercising

• I somehow hit a metabolic switch that causes my body to burn more energy or access body fat more easily (I wish I knew what the switch was.)

It’s almost as if the body is a dynamic system
adjusting inputs based on outputs and outputs based on inputs.

Even the thermostat in your house has the required level of complexity to adjust to changing variables. Our bodies are infinitely more complicated. Of course a self-regulating system roaming through nature will have developed feedback mechanisms to adjust to its environment.

The lipostat theory of obesity is quite popular in mainstream obesity science. It essentially posits that there is a sort of thermostat in the body. But instead of regulating the temperature (although we have that, too) it regulates desired levels of body fat.

It’s not quite clear where this mechanism resides in the body or how it works, but it’s easy enough to test that something like it exists:

• Start water fasting right now and let me know when you first get symptoms of caloric deprivation: dizziness, constant hunger, unexplainable thoughts of food, increased sense of (food) smell, increased adrenaline response, trouble falling and staying asleep.

• Overeat a ton of fatty red meat and let me know if your body temperature increases, you start sweating, and your body tells you to stop eating.

If anyone denies these obvious phenomena, which are simple enough to test, then we have a serious case of spherical cow science on our hands. Who am I going to believe, you or my lying eyes?

You could only believe that these falsehoods follow from CICO by denying what modern obesity science has known for several decades now: you cannot arbitrarily manipulate either CI or CO and expect the other to just stay fixed.

That would be as silly as opening a window when it’s cold out and then being surprised the thermostat will drive up heating to compensate.

CICO misses the question: how do we sustainably create negative energy balance?

Yes, CICO. Welcome. Now can we start the discussion of how one consistently takes in less calories than he puts out? That’s kind of the whole question, isn’t it?

CICO as an answer clearly misses this question. It’s no more the answer to “How do I lose fat?” than “Make more than you spend” is the answer to “How do I get richer?”

Useful answers might include “Get a degree” or “Polish your resume” or “Work long hours” or “Go to church with the CEO.” Reciting an accounting tautology is useless.

There is a particular sub-sect of CICO bot that will reply that “Every way of creating a caloric deficit works” or even “works the same.” Clearly these people have not heard that we have an obesity epidemic on our hands.

Almost no way of creating sustained caloric deficits works, especially in practice.

Nonetheless deficits can be a useful way of thinking. But we need to differentiate between what we’ll call the External and Internal Caloric Deficits.

External Caloric Deficit

This is the deficit your body has vs. the rest of the world. Think of it like the Current Account Deficit your country has with other countries. Every calorie of energy that enters your body must come from outside of it (presumably via food) and leave as heat, motion, or similar expenditure of energy.

When we talk about a “caloric deficit” we typically mean the external deficit that our body has with the world. Let’s illustrate by way of an exemplary man whom we will call Vitruvius:

CI = 1,800kcal, CO = 2,000kcal, deficit = 200kcal

Impossible Deficit

But if the model was truly as simple as that, couldn’t we just jack up our Calories Out with tons of exercise and eat (almost) nothing, creating a crazy deficit? The obvious solution is to run marathons on a water fast, right?

CI = 200kcal, CO = 3,000kcal, deficit = … 2,800kcal? Really?

Almost nobody’s body is going to be able to come up with 2,800kcal/day to bridge this deficit. Not only can you easily try this by water fasting for prolonged periods (say, 3+ days), there are of course studies on this. Turns out the body can only metabolize so much fat in any given time period!

Poor Vitruvius would experience terrible caloric deprivation symptoms and crushing hunger if we made him do this.

Internal Caloric Deficit/Surplus

So let me introduce another tautological accounting entity: the internal caloric deficit (or surplus). The body isn’t one giant vat of calories with food goop drooping in on the top and falling out of a hole at the bottom. There are complicated mechanisms converting the food chemicals into nutrients, triglycerides, glucose, ketones, all kinds of stuff. The internal deficit is still a massive oversimplification but it allows us to explain things that the naive CICO bots have to hand wave away or pretend don’t exist.

Intermission

Q: Your “internal caloric deficit” isn’t real! There’s no such thing! You just made it up!

A: Yes. Just like the “external” caloric deficit. There is no physical concept where motion and heat somehow gets deducted from the stuff you put in your mouth. It’s just an accounting entity and so is mine.

Let’s assume the optimal case as described above and add the internal deficit/surplus by (arbitrarily) assuming that our friend Vitruvius can metabolize 1,000kcal worth of his body fat per day:

CI = 1,800kcal, CO = 2,000kcal, ext. deficit = 200kcal, int. surplus 800kcal

As we can see Vitruvius is able to handle the moderate external deficit just fine because he is running an internal surplus. He could do more!

External Deficit vs. Internal Available Energy

Let us reconstruct the crazy scenario from before. Poor Vitruvius has to run a marathon and can only eat 200kcal per day. Infinite fat loss, amirite? CICO buddy!

Of course not.

Vitruvius can still only access the roughly 1,000kcal/day from his body fat storage.

Poor Vitruvius! The ext. deficit is much too large to be filled by energy available from his body fat.

The obvious response everyone who’s ever seriously dieted has experienced: Vitruvius’ body will turn down the metabolism as far as possible to save energy. At the same time it will increase our poor friend’s appetite, hunger, and adrenaline. Vitruvius will have a hard time falling asleep with his body constantly reminding him that it’s starving. He will be thinking of food without pause.

Vitruvius’ body has begun the caloric deprivation/starvation response.

Now let’s look at a similar scenario but with our new helpful idea the internal deficit. In this scenario Vitruvius isn’t doing any extra exercise but he’s only allowed to eat 500kcal per day. So his external deficit isn’t as crazy as before but still 50% higher than his available body fat storage can provide for.

Ext. deficit = 1,500kcal, available energy from body fat = 1,000kcal, int. deficit = 500kcal

This is what I mean in my post about The Definition of Diet Success when I say that a diet based on a deficit cannot work in the long run.

If you run an INTERNAL CALORIC DEFICIT, while you can fight your own biochemistry with willpower for some time, you WILL run into caloric bankruptcy sooner or later.

Deficits are Necessary to lose Fat but Impossible

Whaaaat! Crazy, right?! Two things are true at the same time:

1. We need to create a caloric deficit to lose fat

2. We can’t create a caloric deficit or the diet will fail

Of course it’s not crazy at all with the help of our new idea the external vs. internal caloric deficit. Let’s rephrase it:

1. We need to create an external caloric deficit to lose fat

2. We can’t create an internal caloric deficit or the diet will fail

No contradiction at all.

This is NOT about slow fat loss. No Sir.

I can already hear the “moderate” people from the “reasonable” crowd nodding their heads in agreement.

WRONG!
Slow fat loss is for people who don’t know any better.
We know better.

Now that we have the concept of the internal deficit and energy available from our own body fat what could we possibly do? Let’s..

Turn it to 11, get it? Jeez, I have to explain everything, don’t I. So there’s this show…

Remember our goal is to lose fat. That means we want to maximize the blue section from Vitruvius’ graphic without hitting the orange internal deficit.

After all the 1,000kcal available from body fat storage was selected totally arbitrarily. It’s not fixed, just as CI and CO aren’t fixed.

Incidentally the actual value of the red “total energy expenditure” or the external deficit are not interesting to us whatsoever. They will probably be high but that’s not what we care about.

The switches we want to flip all concern the blue “energy available from body fat” and not the red “Calories Out” or green “Calories In.” If those incidentally move while we maximize our blue bar then that’s fine but we’re probably wasting our time even looking at them.

In eating to maximize body fat burned our levers are neither Calories In nor Calories Out.
We need to maximize our energy burned from body fat without getting into an internal deficit. CI/CO are irrelevant. Acting on them is like pushing on a string.

Let’s imagine turning our metabolism to 11 and not even eating at a deficit. What would happen?

CI=CO, metabolism set to Ludicrous Speed. Energy expenditure will increase dramatically, his body will practically force Vitruvius to move. Appetite will be massively suppressed.

This pressure on both CI & CO will put Vitruvius’ body into a new equilibrium:

Vitruvius has a whopping CI = 2,300kcal, 1,100kcal or more energy available from body fat storage, and who cares about CO?

If this seems familiar to you, Beloved Reader, it is of course the macros for my current diet, ex150.

Haha, yes. It is I, Vitruvius! Just kidding my name isn’t really Vitruvius.

But I believe ex150 demonstrates pretty well how you can perfectly comply with the First Law of Thermodynamics while not give a flying kite about Calories Out and eating Calories In to satiety. CICO, bro! Do you even deficit? Yes, Sir, I do definitely deficit.

Now I will admit that I stumbled upon this rather by accident and I currently do not know what the switches are that I’m apparently turning to 11.

Something something saturated fat?

Keep your TV set tuned to this channel.

PS: The Sad But Common Case

Didn’t want to end on a sad note but this case is probably the default for most dieters. The end result after years or decades of restricting calories, driving your metabolism into the ground, unable to ever feel satiety on a deep mitochondrial level. This is no way to live, friends. Embrace the heavy cream! The heavy cream is your friend!

Low caloric intake stomping on Vitruvius’ face forever. What is wrong with his eye?! I missed that the entire time.