What You’re Actually Running On
The Vitality Series, Part II
Note: Nutrition has nuance. Nothing said in this post is medical advice. There is a reason that Registered Dietitian is an advanced degree. We take broad strokes in this post, and it is so more people can have a better understanding of not only what fuels our body but also a basic understanding of how.
In the Vitality Series, Part I, we talked about houses made of brick and houses made of mud. The essential concept of the idea, which was reductionist by design, was equating what you put into your body is what your body will be made of.
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I started this post by leaning back into that analogy, deleted the entire post, because it felt like I was really stretching to make it work. So, I am going to leave it at that and move on to explaining more of Vitality in regards to our framework, The Ardent Way.
Our bodies have three ways to create energy, not one, and they all run on different fuel. They also last different amounts of time and, for the most part, we do not pay a lot of attention to this when we are “eating healthy.”
Three systems
Everything you do runs on adenosine triphosphate (ATP). Every step, every breath, everything. Your body has three separate ways to produce ATP, and you transition between the pathways depending on the intensity and length of the task (Gastin, 2001).
Phosphagen. You have about ten seconds, so think a maximal lift, a sprint, or jumping out of the way of a runaway train. You can pull on this pathway in something like the opening run at a HYROX race. Hit the first ten seconds hard and then fall into your predetermined race pace for the remainder of the 1000m, which will pull from a separate pathway. Once this pathway is spent, it takes four to five minutes of doing nothing for it to return (Gastin, 2001).
Glycolytic. Ten seconds up to two minutes. Think 400m run, or reaching the last thirty seconds of a sled push where this pathway is hitting its absolute limit and your legs feel like they want to quit. This system is powered through sugar, blood glucose and muscle glycogen (Gastin, 2001).
Oxidative. You have gone past the two minute mark, meaning a majority of your life. This pathway requires oxygen and uses fat and carbs as fuel. An easy pace will lean more toward using fat as fuel and shift to carbs the harder you push (Brooks & Mercier, 1994).
Another name for these systems is phosphocreatine, lactate, and aerobic. Same three things, and you are not going to be quizzed on this, so no worries.
What feeds these systems
In regards to these systems, stored energy in the muscle, sugar in your blood, sugar packed into the muscle, and body fat fuel the output.
Do you notice something missing from the fuel list?
Protein shows up as a fuel source one time, at the bottom of the aerobic pathway, and it produces less energy than everything else (Gastin, 2001). This is not a subjective statement, it’s on a chart, so it must be true.
Ok, if protein is not fuel, what is it for?
Protein is what you are made of. Muscle, tendons, ligaments, all the bits and pieces holding you together. When you train, you are intentionally doing damage to these tissues, and protein is what our body uses to rebuild it. When your body is burning protein for energy, it is not using that protein to repair itself. (I almost went back to the brick house analogy, but I stopped myself.)
Most, not all, are not eating enough protein
The official recommendation is 0.8 grams per kilo of body weight. For those of us who never got on board with the metric system, and I think it is time we ditch the Imperial system, divide your bodyweight in pounds by 2.2 to get kilograms, then multiply by 0.8. For a 180-pound person that is about 65 grams.
A study in 2018 made it known that 0.8 grams per kilo is not enough for someone who is active and wants to support lean mass (Morton et al., 2018).
In 2022, a study ran the dose response to figure out how much protein is needed to support growth and where intake stops producing results. Strength gains kept improving with more protein up to about 1.5 grams per kilogram per day and then leveled off (Tagawa et al., 2022).
So, that is about 123 grams for a 180 lb person.
What did you eat yesterday? Did you meet your minimum recommended protein intake? Track it for a few days without changing anything and see where you stand. You need to know where you have been before you can make a plan to get to where you are going.
PS, the 30 gram thing is dead
If you have paid attention to protein intake, or you have been in the health and wellness sphere long enough, you have probably heard that your body can only handle 20 to 30 grams of protein in one sitting and the rest is wasted.
In 2023 a study tested this long-held belief by using labeled amino acid tracers to track protein response post workout. The researchers used a no-protein group, a 25 g group, and a 100 g group. The 100 gram dose produced a bigger response, and they found no evidence the excess protein was turned into expensive urine (Trommelen et al., 2023).
This means, if you can only eat two big meals a day and a snack, you’re good. Hit your protein number.
Back to fuel
Glycogen comes from carbohydrates. No carbohydrates and your glycolytic system has no fuel to burn. The middle pathway is also known as lactate and is anaerobic. Think 400m sprint or a medium to high intensity.
This was tested in 2024 by a group of researchers who took competitive middle-distance runners and put them through a workout, fed them very few carbs or a lot of carbs over two days, and then had them run a 1500 meter time trial (Venckunas et al., 2024).
The low-carb group had a 2% drop in performance.
2%? This may not sound like much, but you spread that out over time and you are leaving a lot of performance on the table. I have witnessed people train hard while cutting carbs because somewhere along the way someone told them that is what they need to do, maybe a bodybuilder.
Sidebar: Did you know bodybuilders are at their weakest during a show? That look is not normal. That is dedication mixed with suffering. I am not knocking it, I respect what it takes to get there, but I think we need to be honest with ourselves and not use that aesthetic as something to strive for in health, unless you are trying to be a bodybuilder. Here are some examples.
Back to the point. Inevitably they, the carb cutter, end up hitting a wall and performance drops, and they start to struggle. Yes, there are scenarios where cutting carbs is the right call. Like anything there is nuance, and we are taking some broad strokes.
What about fat? You need it for your aerobic system and it is used to build your cell membranes. Certain vitamins cannot be absorbed without it, and your hormones need it to function properly (National Institutes of Health, Office of Dietary Supplements).
Cutting it to zero doesn’t make you lean. It makes you tired, messes with your hormones, and makes you feel worse. When you feel worse, because true health is not just a number on the scale or a body fat percentage, you will struggle staying with a program and being consistent.
The goal should be longevity in wellness, not touching some abstract number for a moment in an unsustainable way, and then falling directly back into old habits. Sometimes, ending up worse than when you started.
What we think
Nutrition at Ardent is not a meal plan telling you to eat chicken and rice for six weeks. If you are like me, you have probably tried it and you are probably not currently doing it.
We strive to treat food and training as a system, Vitality. Training, regardless of the type, is a signal which tells your body what to build. The food you eat dictates if your body can actually act on the signal or has to ignore it. You can have the perfect training plan by the smartest trainer, but if you do not have the proper fuel for your body to respond to this perfect signal, well, you will never see the results you are hoping for.
In long-term, sustainable wellness, and trying to live your best life, you have to pay attention to fitness and nutrition. This is why, in the Ardent Way, Vitality encompasses both. We also understand that true change is tough and sometimes the most space someone has is just showing up, and we are here for that too. But, in this journey, if you want to see the results you are working toward, you need to treat training and nutrition as a system and not two separate programs.
Two things you can do this week
First, find out what the minimum amount of protein you should be taking in per day, and try to hit that number four out of seven days before you do anything else.
Take your bodyweight in pounds, divide by 2.2 to get kilograms, then take in at least that many grams of protein per day.
Remember, the official minimum is 0.8 grams per kilo, but that minimum was written for someone who doesn’t train. Pick anywhere from 1 gram per kilogram to 1.5 grams per kilogram a day. If you are someone who generally eats less than 0.8 grams per kilogram per day currently, don’t shoot the moon and bump it to 1.5. Start at 1 gram per kilogram and see how you feel.
Second, eat carbs on the days you train hard, before and after.
That is it. Yes, there is way more to nutrition than those two statements, but this is a starting point. Work on these two things and you will probably be ahead of most people you see in the gym. Once you are consistently fueling your body you can go deeper down the nutrition rabbit hole, but keeping it simple in the beginning will help create the consistency which will then create the space to take it further.
In Part III of Vitality, we are going to push past food and get more into health span vs. lifespan. If you remember the idea of compression of morbidity from Part I, we will dig deeper into the idea of living your best life. It is not just about more years, but better years, and we will unpack what successful aging actually means.
Get Stronger. Live Longer.
Sources
Brooks, G. A., & Mercier, J. (1994). Balance of carbohydrate and lipid utilization during exercise: The “crossover” concept. Journal of Applied Physiology, 76(6), 2253-2261. https://doi.org/10.1152/jappl.1994.76.6.2253
Gastin, P. B. (2001). Energy system interaction and relative contribution during maximal exercise. Sports Medicine, 31(10), 725-741. https://doi.org/10.2165/00007256-200131100-00003
Morton, R. W., Murphy, K. T., McKellar, S. R., Schoenfeld, B. J., Henselmans, M., Helms, E., Aragon, A. A., Devries, M. C., Banfield, L., Krieger, J. W., & Phillips, S. M. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine, 52(6), 376-384. https://doi.org/10.1136/bjsports-2017-097608
National Institutes of Health, Office of Dietary Supplements. Vitamin A, Vitamin D, Vitamin E, and Vitamin K fact sheets.https://ods.od.nih.gov/factsheets/
Tagawa, R., Watanabe, D., Ito, K., Otsuyama, T., Nakayama, K., Sanbongi, C., & Miyachi, M. (2022). Synergistic effect of increased total protein intake and strength training on muscle strength: A dose-response meta-analysis of randomized controlled trials. Sports Medicine - Open, 8, 110. https://doi.org/10.1186/s40798-022-00508-w
Trommelen, J., van Lieshout, G. A. A., Nyakayiru, J., Holwerda, A. M., Smeets, J. S. J., Hendriks, F. K., van Kranenburg, J. M. X., Zorenc, A. H., Senden, J. M., Goessens, J. P. B., Gijsen, A. P., & van Loon, L. J. C. (2023). The anabolic response to protein ingestion during recovery from exercise has no upper limit in magnitude and duration in vivo in humans. Cell Reports Medicine, 4(12), 101324. https://doi.org/10.1016/j.xcrm.2023.101324
Venckunas, T., Minderis, P., Silinskas, V., Buliuolis, A., Maughan, R. J., & Kamandulis, S. (2024). Effect of low vs. high carbohydrate intake after glycogen-depleting workout on subsequent 1500 m run performance in high-level runners. Nutrients, 16(16), 2763. https://doi.org/10.3390/nu16162763