The Week Muscle ‘Disappears’ (But Doesn’t)

In this short Friday episode, Dr. Matthea Rentea breaks down a common body composition mistake that causes unnecessary panic: apparent muscle loss that isn’t real.

She explains two very common scenarios where body composition scans can falsely suggest a significant drop in skeletal muscle:

• After an illness (like flu or viral infections)
• After time away from regular strength training, such as vacation

Dr. Rentea explains how temporary drops in muscle glycogen — not true muscle loss — can skew body composition results, and why this typically resolves within a few weeks of returning to normal routines.

Key takeaways:

• Rapid “muscle loss” on body composition scans is often not real
• Illness and vacations commonly affect glycogen, not muscle tissue
• True muscle gain and loss happen much more slowly
• The best response is consistency, not panic-driven changes

She also shares a preview of an upcoming mini-teaching focused on how to properly interpret body composition reports — something most people have never been taught to do in a practical, clinical way. Get on my email list here to not miss this. 

If your January feels a little wobbly, this episode is your reminder to refocus, return to your routines, and keep moving forward!

All of the information on this podcast is for general informational purposes only. Please talk to your physician and medical team about what is right for you. No medical advice is being on this podcast.

If you live in Indiana or Illinois and want to work with doctor Matthea Rentea, you can find out more on www.RenteaClinic.com

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Transcript

0:29

Welcome back to another episode. This is our short Friday segment where I talk about something just for a few minutes. But if you're a newer listener, Mondays are our regular longer episode. Just so you know, I know we have a lot of new listeners, and I don't want you to be confused. I'm gonna talk about something that I've been seeing a lot this week, and I want all of you not to be tripped up on it. When you're tracking body composition, you're looking at pounds of body fat and pounds of skeletal muscle. And in my clinic, I track this monthly with my patients and we make. Realistic adjustments both to nutrition timing of nutrition and what they're eating as well as. Exercise and sleep. We're working on a lot of things based on what's happening. There are two scenarios where it looks like you lost a bunch of muscle and you didn't, and I don't want you to freak out about it. Here are the two things I see most commonly this time of year. Number one, someone gets sick in some capacity. Let's say the flu right now, flu A is vicious and it is, it's getting people right and left around me, and typically people are sick for a few days with that. Maybe even up to five days to seven days, so you have this period where you're really struggling with oral intake. You are not getting the protein, you're definitely not working out, you're febrile and trying to hold on. If you get on the scale, maybe anytime within a week or two after that, it might look like you lost two to three pounds of muscle you did not because you were not working out. Because you are not doing that strength training glycogen, which is think the carbohydrate stores in the muscle that goes down and it looks like you had this precipitous drop, but that is not true. The other scenario where I see this happen is with vacation, same thing happens. You go on vacation, you are actually very active. You might be walking 20, 30,000 steps a day depending on where you are. But most people, if you had a really. Regular exercise routine that included strength training you might not be doing that on vacation. So again, you come back and you think, well, I didn't gain weight. The scale actually looks down, but it looks like it's all muscle. Again, that's just not reality. Do not worry about that. What I typically see is if you come back, you get back into your same routines within three weeks. Within a month of when that thing ended, you are right back to where you were. Here's the teaching moment. It's not real skeletal muscle loss when you, within a three, four week period, recover right back to where you were. Most people are not able to put on two to three pounds a muscle within a month. That's not happening at best, maybe half a pound. Again, it, it varies based on the person and what they're doing, but. The teaching moment is that recovery. It's expected, it's normal, and I want you to know this because I don't want you to have this moment of saying, oh my gosh, I lost all this muscle and I need to change all these things. No, you just need to get back to what you're regularly doing. I'm bringing this up now because a lot of people, number one, I'm seeing a lot of patients that have come back from the holiday times, or a lot of people sometimes take vacation in January, February because it's a hard time of year and they wanna lighten the mood a little bit for themselves, or people are getting a lot of viral illnesses this time of year, and so hopefully this is helpful to you and can help someone to not freak out when this is happening and really get the absolute best results. I am putting together a little mini teaching on interpreting body compositions and things like this are what I'm going to include. Most people do not know how to read a body composition report and actually know what it says and know practically what to do with it. And I wanna say this, it does not exist anywhere I've looked. No one has a masterclass on it. No one has anything on it. Where it's easy to understand and practical and the thing that's most important where there's the clinical understanding behind it, it is no good to just look at numbers if you don't know what to do with it in the real world. So that's gonna be coming out soon with me. If you're not on my email list, I'll have the link down below where you can get on it, and then that way you'll be notified when this comes out soon because this is the type of information that I wanna make sure that you learn. I hope that this year is starting off strong for you. Keep in mind when you're listening to this, we are two weeks into January. Scary. I know. If it's felt a little bit wobbly, this is your chance to refocus, to think about what do I wanna do? Take the first step in that direction. I hope that you have a great rest of the week and we'll talk Monday.