Haha, footnote 5 came in exactly at the time I was wondering that very thing! Wondering how this works for maybe not so much weight, but a slight paunch. I guess if the fat is what gets lost, that could work.
Yes, fat is fat! My experience has been that after a long backpacking trip I come back much leaner with far less muscle loss than you'd expect, given total weight loss. Granted, my pack weighs more than yours, as does everyone else's. :)
Great article, Michael. Followed your stuff for awhile. I would add my anecdotal evidence from a few backpacking trips, including a 6 day one over Mt. Whitney, is that my hiking buddy and I noticed we ate less on the trip. Other hikers mentioned the same thing. We thought it was the body conserving energy because it was in an unknown environment, but sounds like it could mirror the findings here, that the body wanted to shed weight.
Good question Glen. I think the concept is that the Gravitostat is one "fat loss" lever. So I see no reason why it wouldn't work for a "slight paunch." However, I don't think the literature favors spot reduction of subcutaneous fat as a real phenomenon beyond the fact that hormonal imbalances can cause different fat distribution patterns (e.g. a Cushing-type body shape when there are high levels of cortisol). Generally your body will lose and gain fat first where it's primed to do so. This appears to be mostly determined by genetics. All that said, you can spot "increase" muscle, which can change your body shape quite effectively. Furthermore, might be a slight exception for visceral fat reduction, which I will cover in an upcoming letter at https://StayCuriousMetabolism.com
Thank you! I love it when really smart people share stuff with the rest of us. I probably have genetics at least somewhat in my favor at 6’4” and 180. I was planning on starting at the gym when I was 70, might have to move that up a few years. Thanks for the insights!
I loved this article. My wife always gives me funny looks when I wear my pack on our walks so now I can be nerdy with the science.
How do we use this when trying to add muscle? I understand wearing it can curb appetite to help lose weight but would it be smart to not ruck if trying to add a few pounds of muscle?
Good question Dan. The human studies in question used lighter weighted vests for long periods of time. I think "this is the way" for appetite reduction, i.e. lower weight, longer duration. Heavier weights for shorter durations (e.g. a 40 lb pack on an up hill hike) will more likely challange your muscles in a manner that favors muscular growth. Or, if you're walking flat with your 40 lb pack, toss in some lunges here and there. How does that sound? What other questions do you have and/or topic you want to learn about?
When I wear a weighted vest (which I love doing) my knee becomes quite painful and swells. Any thoughts or suggestions, anyone?? I'm 5'3.5, 126 pounds.
Try walking backwards 10 minutes a day, 3 to 5 times a week, to help with pain. It might help. It helped my old knees and I continue to do it. Keep at it. Charlie
So I’m 6 weeks post hip replacement and just recently cleared for outside exercise. I’m walking a mile every other day at the moment and pairing that with body weight exercises using my TRX system, and wearing a 20 lb weight vest.
That weight vest adds more to the workout and I’ll start incorporating it on my walks going forward
I got a new hip in 2023, did rehab then started walking. Added weight lifting, Martial arts, hip mobility slowly as I could tolerate. After a few months, worked up to 10000 steps a day with other training interspersed. Walked backwards for knee pain (Knees over toes guy, Ben Patrick). Over 2024 lost ~30 lbs, 4" on love handles (I was unable to train consistently for 2 years before hip replacement). Go slow but steady, and you should improve dramatically. I was 73/74 years old during this period. You can do it, Charlie
I have walked the Camino and heard of an interesting study of Camino walkers (who carry their stuff in a backpack which is about 10% of their body weight) where they lost weight (mostly fat) during a month-long walk. I also lost nearly 10 pounds after doing a 2-week Camino, and so far have kept most of it off. Sorry I don’t have a reference but this article explains how that would work.
That's a good question Kevin. The human studies in question used lighter weighted vests for long periods of time. I think "this is the way" for appetite reduction, i.e. lower weight, longer duration. But we do not know the "minimum effective dose" when it comes to duration. If you want me to toss outa. number, I'd say 10% body weight for 4-6 hours per day might be the minimum effective dose. The point: for appetite, it's probably long duration & light weight. By contrast, heavier weights for shorter durations (e.g. a 40 lb pack on an up hill hike) will more likely challange your muscles in a manner that favors muscular growth.
Hi Nick. This is so cool! Can you comment on weight regain - in particular the human studies where the vest people did not regain the weight vs the bird studies where they did regain the weight. Curious to know if we have to do this forever. Thanks!
Early comment before reading answer. Here goes: weight vest group increased muscle mass thru fighting gravity during wearing period (standing, sitting, bending, walking, etc). Increased basal metabolism due to muscle increase, use more calories daily, thus less weight gain after study. Also extra weight could have psychological effect by increased daily exertion, resulting in desire to eat less.
The technical stuff made my head hurt. On a less joyful note, I was sorry to hear that the lodge and structures on the Grand Canyon north rim burned down. A lot of future R2R’s will be impacted for who knows how long.
My hypothesis on RCT 2 (before reading the rest of the post).
The Weighted Vest (WV) group actually lost more fat weight but also added muscle so the total weight loss looked the same. The muscle gained then continued to burn calories across the 18 months after the study.
2% taught me about Go Ruck which I have adopted in my daily training routine. 22% of my body weight for 30 min is a sure enough stress point. Most days I will leave on the 40 lb ruck and add a Kaatsu device then grab the TRX bands and do squats etc. After burning out of hitting the gym I got creative and it has been very effective for me.
Thank you to everyone for reading. I've gone through the comments here, on my new YouTube video (released 2h ago as I write this https://youtu.be/d5bwEQtjfzk) and on my Substack and want to highlight 3 Common Q&A. Keep the Q coming! If there's a lot of interest, maybe we will do a round 2 ;)
1. Why do those with obesity remain obese? Shouldn’t the gravitostat help them lose weight?
If the gravitostat were the only lever determining obesity, the answer would be yes. Alas, it’s not. Obesity is a complex, multifactorial condition with many contributing independent variables—including diet quality and composition, hormonal imbalances, sedentary lifestyle, and sociopsychological factors. The data on the gravitostat do not diminish the importance of conventional fundamentals.
That said, one way to think about it is that these other variables help establish a body’s weight range, and the gravitostat then acts to help maintain that range.By way of example: if you are stressed, sleep-deprived, and eat a low-quality diet, your weight set range may be 250–300 lbs, rather than 150–200 lbs. Thus, the gravitostat mechanism only kicks in at a higher threshold. Hopefully that makes sense.
2. Would weighted blankets work?
Probably not, no. While they do provide increased gravitational forces over long durations, the nature of the compression forces is such that they aren’t acting on your long bones in the same way, nor are they additive to the gravitational forces imposed by your body weight pressing from your head to your feet when you’re standing. Sorry. Wouldn’t that be a nice hack?!
3. Running provides high-impact compressive forces. Is this a reason runners are usually skinny?
This is a great question and it’s certainly an interesting hypothesis. That said, I don’t think the gravitational/compression forces are sustained over a long enough duration for gravity to play a very significant role—at least not in a way that would “trick” your body into thinking it’s heavier. You can’t run for 6 hours per day consistently.
However, there may be another layer. Consider this: evolutionary logic suggests the gravitostat exists to ensure the body remains lean enough to be adaptively agile. It’s possible the brain could adjust the gravitostat threshold if it learns it needs to be moving more, as signaled by running. Does that make sense? It’s just a hypothesis, but an interesting one.
This Spring I started rucking with the intention of losing weight. I started at 202 and now I am at 176. I want to get to 170 and will be there soon. Another consequence is my waistline. I started at 36 waist pants and now wear 32 waist pants. Try it, it works.
Can you modify the post summary of your emails you send out to be an actual summary of the post? It currently reads as an overview of what we'll read but doesn't summarize the take aways from the post, which is what I expect every time I see it even though I've been subscribed for a year or so. I understand that might be problematic for non-subscribed readers though.
This is so cool! Great article Michael!
Glad you enjoy it Bradly. What else would you like to learn about?
Haha, footnote 5 came in exactly at the time I was wondering that very thing! Wondering how this works for maybe not so much weight, but a slight paunch. I guess if the fat is what gets lost, that could work.
Yes, fat is fat! My experience has been that after a long backpacking trip I come back much leaner with far less muscle loss than you'd expect, given total weight loss. Granted, my pack weighs more than yours, as does everyone else's. :)
Great article, Michael. Followed your stuff for awhile. I would add my anecdotal evidence from a few backpacking trips, including a 6 day one over Mt. Whitney, is that my hiking buddy and I noticed we ate less on the trip. Other hikers mentioned the same thing. We thought it was the body conserving energy because it was in an unknown environment, but sounds like it could mirror the findings here, that the body wanted to shed weight.
My pack may be lighter, but I’m also decades older than you, which could impact the results. Only way to find out is to get a weight vest.
Good question Glen. I think the concept is that the Gravitostat is one "fat loss" lever. So I see no reason why it wouldn't work for a "slight paunch." However, I don't think the literature favors spot reduction of subcutaneous fat as a real phenomenon beyond the fact that hormonal imbalances can cause different fat distribution patterns (e.g. a Cushing-type body shape when there are high levels of cortisol). Generally your body will lose and gain fat first where it's primed to do so. This appears to be mostly determined by genetics. All that said, you can spot "increase" muscle, which can change your body shape quite effectively. Furthermore, might be a slight exception for visceral fat reduction, which I will cover in an upcoming letter at https://StayCuriousMetabolism.com
Thank you! I love it when really smart people share stuff with the rest of us. I probably have genetics at least somewhat in my favor at 6’4” and 180. I was planning on starting at the gym when I was 70, might have to move that up a few years. Thanks for the insights!
I loved this article. My wife always gives me funny looks when I wear my pack on our walks so now I can be nerdy with the science.
How do we use this when trying to add muscle? I understand wearing it can curb appetite to help lose weight but would it be smart to not ruck if trying to add a few pounds of muscle?
Good question Dan. The human studies in question used lighter weighted vests for long periods of time. I think "this is the way" for appetite reduction, i.e. lower weight, longer duration. Heavier weights for shorter durations (e.g. a 40 lb pack on an up hill hike) will more likely challange your muscles in a manner that favors muscular growth. Or, if you're walking flat with your 40 lb pack, toss in some lunges here and there. How does that sound? What other questions do you have and/or topic you want to learn about?
When I wear a weighted vest (which I love doing) my knee becomes quite painful and swells. Any thoughts or suggestions, anyone?? I'm 5'3.5, 126 pounds.
How heavy is the vest you're using?
either 12 or 16 pounds
Try walking backwards 10 minutes a day, 3 to 5 times a week, to help with pain. It might help. It helped my old knees and I continue to do it. Keep at it. Charlie
Thanks I’ll start doing that!
So I’m 6 weeks post hip replacement and just recently cleared for outside exercise. I’m walking a mile every other day at the moment and pairing that with body weight exercises using my TRX system, and wearing a 20 lb weight vest.
That weight vest adds more to the workout and I’ll start incorporating it on my walks going forward
Sounds good! Defer to your doctor on how to reintegrate movement. Typically starting with less and ramping up is a good approach.
Oh I am. Only cleared for body weight exercises but I am cleared to wear a weight vest for walking.
I’m only doing things I’m cleared for at the moment.
I got a new hip in 2023, did rehab then started walking. Added weight lifting, Martial arts, hip mobility slowly as I could tolerate. After a few months, worked up to 10000 steps a day with other training interspersed. Walked backwards for knee pain (Knees over toes guy, Ben Patrick). Over 2024 lost ~30 lbs, 4" on love handles (I was unable to train consistently for 2 years before hip replacement). Go slow but steady, and you should improve dramatically. I was 73/74 years old during this period. You can do it, Charlie
Great to know. I’m working on step increase at the moment but going nice and easy and trying to avoid my typical rush to improve fitness.
Thanks for the input
I'll be the one to say that I was really hoping that third study had mice wearing tiny weighted vests.
Would wearing a weighted vest at a standing desk count too?
Yep!
I have walked the Camino and heard of an interesting study of Camino walkers (who carry their stuff in a backpack which is about 10% of their body weight) where they lost weight (mostly fat) during a month-long walk. I also lost nearly 10 pounds after doing a 2-week Camino, and so far have kept most of it off. Sorry I don’t have a reference but this article explains how that would work.
On another note, this study had folks wearing vests for 6-8 hours a day. How much time do you need to wear this, I.e., the dosage, to get the effect?
That's a good question Kevin. The human studies in question used lighter weighted vests for long periods of time. I think "this is the way" for appetite reduction, i.e. lower weight, longer duration. But we do not know the "minimum effective dose" when it comes to duration. If you want me to toss outa. number, I'd say 10% body weight for 4-6 hours per day might be the minimum effective dose. The point: for appetite, it's probably long duration & light weight. By contrast, heavier weights for shorter durations (e.g. a 40 lb pack on an up hill hike) will more likely challange your muscles in a manner that favors muscular growth.
Hi Nick. This is so cool! Can you comment on weight regain - in particular the human studies where the vest people did not regain the weight vs the bird studies where they did regain the weight. Curious to know if we have to do this forever. Thanks!
Early comment before reading answer. Here goes: weight vest group increased muscle mass thru fighting gravity during wearing period (standing, sitting, bending, walking, etc). Increased basal metabolism due to muscle increase, use more calories daily, thus less weight gain after study. Also extra weight could have psychological effect by increased daily exertion, resulting in desire to eat less.
Good guess. "Bold." Not entirely correct... but that's good! There's something to learn.
The technical stuff made my head hurt. On a less joyful note, I was sorry to hear that the lodge and structures on the Grand Canyon north rim burned down. A lot of future R2R’s will be impacted for who knows how long.
My hypothesis on RCT 2 (before reading the rest of the post).
The Weighted Vest (WV) group actually lost more fat weight but also added muscle so the total weight loss looked the same. The muscle gained then continued to burn calories across the 18 months after the study.
2% taught me about Go Ruck which I have adopted in my daily training routine. 22% of my body weight for 30 min is a sure enough stress point. Most days I will leave on the 40 lb ruck and add a Kaatsu device then grab the TRX bands and do squats etc. After burning out of hitting the gym I got creative and it has been very effective for me.
Common Q&A
Thank you to everyone for reading. I've gone through the comments here, on my new YouTube video (released 2h ago as I write this https://youtu.be/d5bwEQtjfzk) and on my Substack and want to highlight 3 Common Q&A. Keep the Q coming! If there's a lot of interest, maybe we will do a round 2 ;)
1. Why do those with obesity remain obese? Shouldn’t the gravitostat help them lose weight?
If the gravitostat were the only lever determining obesity, the answer would be yes. Alas, it’s not. Obesity is a complex, multifactorial condition with many contributing independent variables—including diet quality and composition, hormonal imbalances, sedentary lifestyle, and sociopsychological factors. The data on the gravitostat do not diminish the importance of conventional fundamentals.
That said, one way to think about it is that these other variables help establish a body’s weight range, and the gravitostat then acts to help maintain that range.By way of example: if you are stressed, sleep-deprived, and eat a low-quality diet, your weight set range may be 250–300 lbs, rather than 150–200 lbs. Thus, the gravitostat mechanism only kicks in at a higher threshold. Hopefully that makes sense.
2. Would weighted blankets work?
Probably not, no. While they do provide increased gravitational forces over long durations, the nature of the compression forces is such that they aren’t acting on your long bones in the same way, nor are they additive to the gravitational forces imposed by your body weight pressing from your head to your feet when you’re standing. Sorry. Wouldn’t that be a nice hack?!
3. Running provides high-impact compressive forces. Is this a reason runners are usually skinny?
This is a great question and it’s certainly an interesting hypothesis. That said, I don’t think the gravitational/compression forces are sustained over a long enough duration for gravity to play a very significant role—at least not in a way that would “trick” your body into thinking it’s heavier. You can’t run for 6 hours per day consistently.
However, there may be another layer. Consider this: evolutionary logic suggests the gravitostat exists to ensure the body remains lean enough to be adaptively agile. It’s possible the brain could adjust the gravitostat threshold if it learns it needs to be moving more, as signaled by running. Does that make sense? It’s just a hypothesis, but an interesting one.
This Spring I started rucking with the intention of losing weight. I started at 202 and now I am at 176. I want to get to 170 and will be there soon. Another consequence is my waistline. I started at 36 waist pants and now wear 32 waist pants. Try it, it works.
Can you modify the post summary of your emails you send out to be an actual summary of the post? It currently reads as an overview of what we'll read but doesn't summarize the take aways from the post, which is what I expect every time I see it even though I've been subscribed for a year or so. I understand that might be problematic for non-subscribed readers though.