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Fasted Training vs Eating Before Workouts: Study Compares the Difference – Thomas DeLauer
This is the official fasted training versus non-fasted training video. What I mean by that is we’re going to look at some of the science between what happens when you train in a completely fasted state, whether it’s overnight or after an intermittent fast, or if you’re training after eating some food.
It’s a common battle that’s occurring on the internet. It’s a common battle that people talk about all the time. Which is better? You get a little bit more power when you’re training with a little bit more energy in your system, but you might get a better response if you’re training in a fasted state. So let’s look at the science, and there’s one particular study that I want to reference that’s going to break it all down and give us some clear cut answers.
But the first thing that I want to talk about before we go into any detail on anything is I want you to stop worrying about if you’re going to lose muscle or not. Here’s the thing, if you work out for long enough, if you work out for long periods of time, yeah, you’re going to burn up some muscle, but if you’re training in a fasted state, the last thing I want you to worry about is losing muscle. Whether you’re a man or woman, it doesn’t matter. You’re not going to lose as much muscle as you think, if any. The fact is you have way too many hormones that are skyrocketing when you’re in a fasted state that far supersede the effects of catabolizing muscle.
You have high amounts of human growth hormone that stop the breakdown of muscle. Okay? But the other thing is once you’ve been fasted for a longer period of time, your liver starts to produce something known as BHB, Beta-Hydroxybutyrate, which is a ketone body. That ketone body stops what is called leucine breakdown or leucine oxidation. Leucine is an amino acid, and that amino acid is at the forefront of catabolism, muscle breakdown. It’s very simple. If we have leucine in the equation, you’re not breaking down muscle. If leucine is oxidizing, you’re breaking down muscle.
In the case of fasting, when you have ketones present from a fast, it doesn’t mean you have to be in ketosis, it just means you’ve been fasted, you have enough of this overall ketone production to make it so that you’re not going to burn up that muscle, and you’re not going to go into that leucine oxidation.
So now that that’s out of the way, let’s truly talk about the difference between training fasted and training fed, and there’s one study in particular that really took a good look at this. It was published in the Journal of Physiology, and it took a look at something entirely different from what we’re used to seeing.
You see, normally the argument for fasted cardio is really simple. It’s kind of bro science, but it kind of makes sense at the same time. People will say that fasted cardio is good simply because you’re burning through all of your glycogen. Glycogen is your stored carbohydrates in your muscle. So they say that because you’re training in a fasted state, you burn through that glycogen, and your body has no choice but to start burning fat because you’ve already gone through the glycogen. That’s a simple theory, and it kind of makes sense, but it’s not the truth. That’s not why fasted cardio is better. That’s not how it works.
So what this study looked at is it looked at something known as intramyocellular lipids. You see inside of our muscles, we have little itty bitty, teeny, tiny bits of fat.
1) Muller AF , et al. (n.d.). Ghrelin drives GH secretion during fasting in man. – PubMed – NCBI. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/11834429
2) Nørrelund H , et al. (n.d.). The protein-retaining effects of growth hormone during fasting involve inhibition of muscle-protein breakdown. – PubMed – NCBI. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/11147801
3) Pan JW , et al. (n.d.). Human brain beta-hydroxybutyrate and lactate increase in fasting-induced ketosis. – PubMed – NCBI. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/11043913
4) Very-low-carbohydrate diets and preservation of muscle mass. (n.d.). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1373635/#B6
5) Exercise in the fasted state facilitates fibre type-specific intramyocellular lipid breakdown and stimulates glycogen resynthesis in humans. (15, April). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1464435/
6) Hormone-sensitive lipase – an overview | ScienceDirect Topics. (n.d.). Retrieved from https://www.sciencedirect.com/topics/neuroscience/hormone-sensitive-lipase