Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...Tell Me More
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.
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!