Keto does not defy the First Rule of Thermodynamics

If there is one thing I love hearing from the CICO world is that you can’t break the 1st rule of thermodynamics.

Here is the rule:

Energy cannot be created or destroyed. It can only change forms.

This is a fair statement. Opposition to the idea that the keto diet allows for the consumption of more food while still losing weight constantly scream that this can’t be true because that breaks the first law!! Well I will show today that it absolutely does not and it is extremely simple minded and unscientific to think that it does.

Let us look first at the simplistic CICO model.

This is literally what they think. We are a simple machine like a car that we pour calories in and then we must run enough to use all those calories or the balance is left in the tank as fat. They honestly think that we are as basic as this.

Let’s look at what really happens.

This is probably even simplified a bit. As you can see, things are not so simple as fuel in minus fuel used equals fat left. There are thousands of processes running in the background that determine what is done with food coming in and the type of food we eat is a dramatic determinant of what happens.

For todays discussion lets just look at what happens with carbs vs fat to make things simple. We will look at them in isolation. Carb only diet vs fat only diet.

Carbohydrate Metabolism:

– Carbs enter as food.
– carbs can consist of fiber (soluble and insoluble), sugars (glucose, fructose, maltose, etc.) and starch. It gets more complex but this is adequate for the discussion.
– Soluble fiber can be digested by the bacteria in the gut to produce short chain fatty acids and used for energy where insoluble cannot. You can already see where this is getting more complex than the CICO model allows.
– Sugars get absorbed right away while starches need to be further broken down which requires slightly more energy than simple sugars. Again it gets more complicated.
– Once everything is broken down to simple sugars then the simple sugars are not yet energy. Insulin is needed to push the glucose out of the blood and into the cells. The glucose then has to go through a process. This is called cellular respiration and looks like this:

This is how ATP, the bodies energy is made. Now the body will only need so much energy, this is your metabolic rate or your TDEE, so if you eat more than you need then the rest will go to store as fat right? Not exactly.

The body likes to protect a certain weight. If more energy comes in then it will do some fun things to try and waste energy. Things like increase NEAT (Non-Exercise Activity Thermogenesis). This is things like fidgeting and blinking. The body will actually make you move more involuntarily just to waste extra energy. See how fun and smart the body is! Now if you constantly consume more carbohydrates than you can store/use then eventually the body will reach a limit where it will not be able to waste as much so there are a couple options.

1. Store it as fat
2. Store it as glycogen
3. Store as blood sugar.

Since blood sugar has to be regulated tightly the storage in blood glucose is not possible above a stable limit so I guess it is fat or glycogen. This is when CICO works exactly right. If you exceed what you can store as glycogen or use then you gain weight.

Now lets look at fat metabolism:

– Fat enters as food.
– It is broken down into fatty acids (short, medium and long chain)
– Long chain have to be packaged into molecules for transport around the body (lipoproteins)
– short and medium chain get passed right through the intestinal walls into the blood and direct to the liver
– Fatty acids do not require insulin to be pushed into cells.

The process of fat going through the system is essentially the same at this point as it is for glucose but instead of the first step being Glycolysis and converting glucose to pyruvate, fat goes through beta-oxidation and is converted directly to AcetylCoA which can be fed directly to the citric acid (kreb’s) cycle. There is alot more to it but I will leave it at that for simplicity. Fat also creates much more ATP (energy) from each of the steps than glucose does.

This is what the process looks like for fat:

Now is where we get to the point of how keto can allow one to eat more while still being compliant to the First Rule.

The difference between fat and carbs for cellular respiration is this:

– Carbs only make 2 AcetylCoA molecules to feed the citric acid cycle. This cycle has a limit of how much AcetylCoA it can process. If by chance there is too much glucose in the system that the cycle gets overloaded then there are only a couple fates for carbs.

1. Storage as glycogen
2. If you are already stocked up on glycogen then it must be stored as fat

– Fat makes many more AcetylCoA than carbs. Even a short chain fatty acid makes 5 acetylCoA. This can quickly jam up the citric acid cycle.

When the cycle gets backed up from fat, something magic happens. Ketones are created from the excess AcetylCoA! It gets better though. wait….

There are three types of ketones that get created. Acetone, Acetoacetate, and Beta-Hydroxybutyrate. Why is this magical? Two of these are wasted. Acetone in the breath (keto breath) and Acetoacetate in the urine. Beyond that, we now have a whole new storage option available that is not available for carbs.

So this is what happens when fat backs up the citric acid cycle:

1. Excess gets converted to ketones
2. Some gets wasted in breath and urine
3. You can store a bunch in your blood.

The big difference comes in when you are consuming carbs and fats together. The carbs have to get used primarily which means the fat will wait in storage while if you limit carbs, fat can be the primary fuel source and it doesn’t have to stay in fat. It can completely fulfill the energy cycles needs and any extra can be converted to ketones for wasting and stored ketone energy.

To summarize:

CICO for carbs meets the laws because the first law says energy must be balanced. It cannot be destroyed or created.

Energy Balance = Energy in – Energy out + Energy Stored (as fat or glycogen)

CICO for fat also meets the law.

Energy Balance = Energy in – Energy out + Energy stored (as fat or ketones) + energy wasted (as ketones)

The reason why you can eat more on keto and still lose weight is because we have additional means of dealing with energy. It can be wasted and stored in an alternate location compared to carbs. There is no defiance of the law.

I hope that all makes sense. I will be doing a youtube video on this in the future as well and hopefully that will make it even more clear.

Keto ON,
Coach Jack

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6 Replies to “Keto does not defy the First Rule of Thermodynamics”

  1. Finally a simple yet science-y way to explain this to CICOcrazed people! Thank you Jack!!!

    if/when you have time could you consider going more in depth on this bit:

    “The big difference comes in when you are consuming carbs and fats together. The carbs have to get used primarily which means the fat will wait in storage”

    specifically, beyond the fat already stored, the fat that is consumed along with carbs undergoes what process to get stored while we use glucose? Cause I had the impression it was stored in fat cells by insulin if in presence of excess glucose (hence why we keep breakfast low fat but highger carbs/protein?) but I suspect I might have got the process wrong?

    1. As far as I am aware, this may not be exact but, most of the fat you consume goes into fat cells directly when you eat it. Even fat induces some insulin response. It is very minor and it is actually from the glycerol component of dietary fat more than the fatty acids.

      When Fat is consumed it is either packaged in chylomicrons, longer chain fatty acids, or passed directly through the intesitinal wall, short chain fatty acids like MCT, then passed to the liver. The stuff passed into the liver is converted directly to AcetylCoA and passed right into the TCA cycle for fuel while the stuff in chylomicrons is passed through the lymph system first then dumped out the thoracic duct, I believe the right side, where it will hit the blood stream and start dumping trigs off to fat cells. This is why MCT is seen as fast energy and a source of quick ketones as it goes right to the liver.

      All of this time fat is still being released from fat cells and also being used for fuel but the rate depends on how much insulin is present. If you just eat fat then you will have fat coming out faster, or at least as fast, than it is going in but if you consume other foods that are more insulinagenic then the input rate will exceed the output rate and your RQ (Respiratory Quotient) will move more towards carb burning and less towards fat burning.

      As the carbs get used up and the insulin lowers, the RQ will drop again and you will move back to a faster rate of fat usage.

      Insulin isn’t an on/off switch for fat cells but more of a rate limiter like a dimmer switch. You can still have fat leaving cells for fuel with insulin present. It is more of a sliding scale. The more insulin the less fat you use and the more glucose you use. There is a point where all fat usage is likely stopped but that would only be at the peak of insulin spike.

      As for the low fat breakfast, that is more because you are already at a point of high insulin due to the dawn effect so you might as well not have more fat going into cells than are coming in. Just allow the insulin to deal with the carbs and protein and take fat out of the equation. Now this could also not work for some. If they don’t have a strong dawn effect then just eating protein and fat might increase insulin to a point where it remains high for too long and they just end up not using fat all morning or longer. This would be the case for severely insulin resistant people. These folks would be better suited to just eat a balanced keto meal and take less of an insulin dump.

      I hope that is what you were looking for. I brain vomit sometimes and too much comes out. 🙂

  2. Brain vomit. Love that 😊😁

    I’ve been basically stalled for a year.. so to be clear, you recommend not eating bacon and eggs for breakfast?

    1. Hmmmm….not at all sure where you got that from. Why would I not recommend bacon and eggs?

      1. Sorry, I seemed to gather that its better not to eat breakfast too early?

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