I am really excited about today’s episode of the podcast. Episode 471, which airs today, is clearing up some major nutrition misconceptions and misunderstandings.
Most of them came up in response to episode 469 on extended fasting.
We’ll tackle a bunch of them, but I want to dive into one specific one right here on the blog.
If you’d rather listen to this blog than read it, please click play. Otherwise, keep reading below.Â
In episode 469 I explained that your body won’t burn your muscle tissue for fuel when you’re fasting, so long as you have a body fat percentage over (approximately) 4-6%.
Someone responded with a disagreement. Her stance is that science PROVES you lose lean mass because some research has shown an increase in urea in the urine during fasting compared to non-fasting.
To get everyone on the same page, urea is a byproduct of protein metabolism. This listener, and some researchers, conclude that protein metabolites in the urine during fasting (when you aren’t consuming protein), prove that your body burns lean muscle during a fast.
WRONG.
It doesn’t prove that. Here’s why:
Metabolizing protein does not mean burning muscle tissue. Understand that lean muscle tissue is NOT the only protein component in your body. Not even close. Could burning lean mass produce an increase of urea in the urine? Yes of course. But that doesn’t mean that increased urea in the urine means you’re burning lean mass.
There are many other (more) logical explanations.
For example: we talked about autophagy, right? In both episodes 469 and 470 we talked about this cellular clean up process where your cells, under certain conditions, are able to eliminate broken, defective or old components.
Guess what? Some of those components (perhaps many of those components) are proteins. So, as we go through this cellular detoxification and clean-up, we will see metabolites of that process in the urine.
If you have questions or rebuttals to this, make sure you listen to episode 471 first because we’ll go more deeply into this issue and many more including:
- Why urine ketones might not reflect if you’re in ketosis or not
- Why you can’t judge a fast exclusively by what happens during a fast (you must consider what happens after the fast)
- What fuels your muscles during a workout when muscle glycogen has been exhausted?
Have other questions or looking for clarification? Let me know and we’ll dive into them here on the blog or on the podcast!
Make it a great day!