Oxidative Priority: Dietary Fuels To the Body

Today’s guest post is generously offered up by Craig Emmerich, husband to—and co-author with—the queen of keto herself, Maria Emmerich. Enjoy!

When we consume macro nutrients, our bodies go through a priority for dealing with them. This priority can be very useful in understanding how our bodies work and how to leverage it for losing weight.

The body doesn’t like having an oversaturation of fuel in the blood at any time. It tightly manages the fuels to avoid dangerous situations like hyperglycemia or blood glucose that is too high. But it also manages and controls other fuels like ketones (beta hydroxybutyrate or BHB levels) and fats (free fatty acids or FFA and triglycerides) to keep them under control and not oversaturate the blood with fuel.

It is like the engine of a car. You don’t want to give the engine too much fuel and blow it up. So the body controls the amount of fuels in the blood to ensure you don’t “blow up.” To do this, the body will address the most important (or potentially most dangerous) fuels first. It does this in a very logical way—in reverse order of storage capacity.

Here is a chart showing the breakdown of oxidative priority for dietary fuels.

Modified Source: Keto. By Maria and Craig Emmerich
Original source: Oxidative Priority, Meal Frequency, and the Energy Economy of Food and Activity: Implications for Longevity, Obesity, and Cardiometabolic Disease, Sinclair, Bremer, et al, February 2017.

The #1 oxidative priority is alcohol because there is zero storage capacity for it. It makes sense that the body would address this first, since it can’t store it anywhere and too high blood alcohol means death.

The second oxidative priority is exogenous ketones. These are ketone salts that raise blood BHB levels. There isn’t a storage site for ketones either, so the body must deal with this before addressing other fuels. That is why exogenous ketones aren’t the best option when trying to lose weight. They displace fat oxidation, keeping fat stored while it uses the exogenous ketones as fuel instead.

The third oxidative priority is protein. Protein is a bit different, as there is a limited storage space for protein, but protein is not a good fuel source. It takes 5 ATP to turn protein into a fuel (glucose through gluconeogenesis) and another 2 ATP to burn in the mitochondria. Why would your body expend 7 ATP for something it can do for 2 ATP by just burning glucose or fat from your body? Protein is only really used as a fuel when other fuels (glucose and fat) are not present and it is forced to use protein. Protein gets preferentially used to stimulate muscle protein synthesis. It builds and repairs lean mass.

The next oxidative priority is carbohydrates. It has a moderate amount of storage capacity at 1,200 to 2,000 calories.

The last oxidative priority is fat. This makes sense, as there is a theoretically unlimited storage capacity for fat. There are people with upwards of 400 pounds of stored body fat, which represents 1.6 million calories.

Oxidative priority can help you understand what happens when you put certain fuels into your body. If you are drinking alcohol while eating carbs and fat, the carbs and fat will primarily go into storage while the body deals with the elevated alcohol.

To understand the power of oxidative priority take the case of an alcoholic. Alcoholics will have very low A1c levels (in the 4s) no matter what they eat! If they eat tons of carbohydrates they will still have an A1c in the 4s because the chronically elevated alcohol levels force the body to store all glucose while dealing with alcohol, creating a low A1c. I am not recommending anyone become an alcoholic to lower A1c level—but quite the opposite actually.

So, what does this mean, and how can you leverage your body’s biology to lose weight?

If you avoid alcohol and exogenous ketones, get a just enough protein to support maintenance of lean mass (about 0.8 times your lean mass in pounds for grams of protein a day), limit the carbs and then reduce dietary fat a bit to force the body to use more stored body fat for fuel you will lose body fat. When you restrict carbs for long enough (4-6 weeks for most people) the body gets used to using fat as its primary fuel (keto adapted). This means it can burn body fat or dietary fat equally well. Eliminating other fuels and keeping dietary fat moderate allows the body to focus on body fat for fuel resulting in fat loss.

That is our bodies system for processing fuels coming in through the diet. Leverage it for improved results and body recomposition.

Craig Emmerich graduated in Electrical Engineering and has always had a systems approach to his work. He followed his wife Maria into the nutrition field and has since dedicated his time researching and looking at nutrition and biology from a systems perspective. Over the last 8 years he has worked with hundreds of clients alongside Maria to help them heal their bodies and lose weight leveraging their biology to make it easy.

Thanks to Craig for today’s keto insights, and thanks to everybody here for stopping in.

You can follow Maria and Craig’s work on their website, Maria Mind Body Health, as well as their subscription site, Keto-Adapted, and their new keto courses.

Questions about dietary fuels and oxidative priority—or other points keto? Share them down below, and have a great end to the week. Take care, folks!

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20 thoughts on “Oxidative Priority: Dietary Fuels To the Body”

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  1. This is a cool analysis of body fuels, thanks Craig.

    My one point of contention is that I think it’s time we make clear that fat adaption and constant ketosis is not always a sustainable solution and definitely not for everyone. I, for example, am a hyper responder to fat/SFA and going Keto causes a skyrocketing of things like LDL particle count. I have no fat to lose, either.

    I know Mark has been vocal in the past about ketosis not always being a long term solution. But passers by on articles like this should definitely get the counter point.

  2. I’ve seen this analysis before, and always had the question – can we really lump “carbohydrates” together like this? Are fructose and glucose metabolized differently for this purpose? Is the storage capacity for energy from fructose and glucose equivalent (i.e., liver vs muscle glycogen)? To what extent is fructose metabolized in a manner that is more similar to alcohol than carbohydrate?

    1. Yes, excellent question, and I wonder the same thing about fats. Since the body stores saturated fats, is there also a higher oxidative priority for unsaturated fats? Does this depend on the state of fat adaptation? In particular, in a fat adapted state, I don’t understand why the oxidative priority would switch from dietary fat to a mixture of dietary and stored fat. It seems like the stored fat would still have a lower priority than the dietary fat, because it wouldn’t make sense to bring fat out of storage if there’s already some circulating fat that could be used. Is there evidence for this, or for the magnitude of the effect?

    2. Great question!

      If we break carbs maybe the priority would be more complex?

  3. Thanks @Craig for sharing your analysis on body fuel. I agree with your point that “body controls the amount of fuels in the blood to ensure you don’t “blow up.” Also, in a new study it shows that Oxidative priority helps to maintain your body weight and cardiometabolic disease.

    But, I request @Mark to please provide your view on @Gerard question?

  4. What about MCTs? Are the ketones produced from the consumption of C8 similar in how the body processes exogenous ketones? Since the point is to get the body to make ketones and burn body fat, are refined MCTs counterproductive? Maybe MCTs help the body adapt to using ketones during the initial Keto adaptation stage, but on the other hand, perhaps it suppresses the body from ramping up the endogenous ketone manufacturing machinery?

  5. Why do you keep saying calories where you really mean kilo calories (or kcal for short)?

    I understand people use this wrong form but an article or a book with any relation to science should get it right.

    It sounds like “a person went on a diet and lost 10 grams”.

  6. Hi @Craig! 🙂 I’m Sammy thank for sharing this analysis on body fuel, this information is beyond helpful.
    I’m 33 and I’ve been trying to lose weight for the past year and a half and tried multiple diet plans, workouts…
    but I can’t seem to reach the results I want. So at this point I’m basically jumping from diet to diet checking out blogs trying to find out what works
    best for me and I was wondering If you would recommend taking any supplements or fat burning products. I found this other blog (trenderreviews.wixsite.com/howtoloseweight) talking about a burning fat product that seems pretty legit but everytime I talk with my friends and family about buying this kind of products everybody tells me that it is a scam and that they usually never work.
    I’m kinda desperate at this point and would really appreciate if you could shed some light about this issue and if you know any good products that I could start using or have heard of that one before.
    I’m looking fordward to start a keto diet so I would also like to know if any losing weight product could conflict with the diet. Thanks!

  7. So once fat adapted, if we only ate protein as specified, our bodies would burn the most fat?

  8. You constantly talk about people who need to lose weight. How about some diet advice for those of us who might want to gain a few pounds?

  9. “Protein is only really used as a fuel when other fuels (glucose and fat) are not present and it is forced to use protein.”

    That wouldn’t mean that protein has priority #5 instead #3 ?
    That’s different from first chart, but agrees with studies that says it’s very difficult to get fat eating protein.

    It would make sense that excluding alcohol and exogenous ketones the priority is glucose, fat, protein.

    Thoughts about it?

  10. Mark and Craig,

    Thank you for an excellent article and a great follow up response as well. I’ve been doing Keto for 4 1/2 years, and there is always more to learn. My question concerns alcohol. I love drinking my 2 or 3 beers every evening. I’m trying to qualify how much fat burning I’m sacrificing by drinking.

    If a 180 pound athletic guy drinks say 2 – 12 ounce, 6% alcohol, 3.4 carb beers, how much liver time am I tying up? I’d like to get an answer in calories, or fat gram equivalents or some way to better understand just what demands I’m putting on my liver, and how much fat burning is not getting done.

    Thanks for your help!
    Ken L

  11. An immediate analysis of dietary fuels has made sure no over-saturation on blood do ever comply. Secondly, Oxidative priority chart has been properly explained. It has become convenient for such health seekers around.

  12. Hi Craig
    I’m an RN and have a question about the keto diet and its efficacy in effecting weight loss in the context of oxidative priority as you’ve described here. If the body preferentially STORES dietary fat over all other macronutrients, and we’re eating 80% of calories as fat on the keto diet, why would the body use existing adipose tissue as an energy source (resulting in weight loss) vs simply getting energy needs met primarily from dietary fat? It seems counterintuitive. Wouldn’t a high protein and low-fat diet be indicated based on oxidative priority to lose weight?

    Thanks so much for your help!

  13. I am surprised at the overall silence in answering the questions posted to this article. Do you plan to answer these, Craig?

  14. This does not accurately summarize Cronise’s paper or reflect the paper’s conclusion. The author also misrepresents the data. Cronise in no way advocates a ketogenic diet.

  15. This is a shameful article.
    Misrepresenting the truth and stealing other peoples work is not the act of people with integrity.
    And, yes, you did steal Ray Cronise’s work. Citing his paper but explicitly removing his name when he was the primary author is the act of shameful people trying to hide something. (Yes, using “et al” to cover the primary authors name is an intentional and shameful act.)
    It doesn’t matter what else was said in this article, these acts discredit the whole thing.