Back in the pandemic days when we weren't supposed to travel far I did 5 k a day. I had to run/walk occasionally and celebrated the end with a PR 10K and my weight didn't budge. I wasn't trying to loose weight but just making sure I got some exercise a day.
From my experience it's just easier to eat less than exercise enough to loose weight. I had my biggest weight loss while eating less and cycling more. The cycling was easier to do for hours at a time so I could contribute to a calorie deficit.
Speaking of calorie deficits I propose that regardless if it is from exercise or eating less your body will adjust some to compensate. For some it compensates more than others which is why it appears easier for some to loose weight than others.
I just don't buy it. I certainly have gained weight doing marathons. People do have a tendency to give themselves permission to eat more if they exercise. Exercise is often appetite stimulating and makes one lazy the rest of the day. Also estimates of energy expenditure are notoriously inaccurate.
The thing that makes me think that the constrained energy model is true is how my brain works after a long run. I’m just not up for tough mental work like writing or reading complex stuff even though I didn’t have to think that much while running. Since the brain needs a lot of energy, could that be part of this?
Is this chiefly a shot across the bows of Herman Pontzer’s work on metabolism (as detailed in his book ‘Burn’)? Any response from his team so far?
Encouraging news for those of us who’d like to think our efforts to exercise are contributing something positive to our body composition goals, even if we know diet is the bigger influence.
It’s one study among many and it’s certainly not the nail in the coffin of the constrained model. Pontzer’s and team also have extensive data (and longer term) that would push back against these findings. He actually responded to me on X!
“This was a 10 day study. Not sure why anyone would think these changes would happen that quickly or necessary show up in RMR. Our work (which they cite but don’t get quite right) suggests the changes take months and don’t always show up in RMR.”
Hmmmm, so it could be a case of ‘it’s not either, it’s both’, depending on time frame and frequency of exercise perhaps? I look forward to watching the debate progress.
It seems to me that, just as the body expends less energy for a given effort in a conditioned athlete, that same body will expend less effort in maintenance at rest. The heart, lungs (diaphragm), and even skeletal muscles get more efficient delivering and utilizing oxygen whether exercising or resting. Using that as a basis (hypothesis) for experiments (studies) should provide more insight than a "compensatory model" hypothesis - in my opinion.
Thanks for that review-- I think the compensatory model needs to be challenged. The primary driver of resting energy expenditure remains lean body mass, and chronic exercise rarely fails to increase or maintain LBM. I do feel that comensatory NEAT and food intake can change considerably in response to exercise sessions, but they are independent of resting energy expenditure.
Brady - nice job as always. I couldn't help but wonder if there's an efficiency element involved in the results? In other words, as I become more fit, EVERYTHING becomes easier - "costing" the body less for each activity performed. It seems that would account for the reduced metabolic cost? I couldn't tell if the researchers noted that possibility?
Wow - I’d never thought of that Brad. Probably something to it, but I would be curious how many calories are “saved” when one’s efficiency improves. My speculation is it wouldn’t be major.
Would this not be easy to demonstrate for someone that uses a power meter on their bike? Faster with the same power or less power for the same speed so long as their weight stayed the same. Unless your body just gets better at converting the calories into power at the pedal.
Back in the pandemic days when we weren't supposed to travel far I did 5 k a day. I had to run/walk occasionally and celebrated the end with a PR 10K and my weight didn't budge. I wasn't trying to loose weight but just making sure I got some exercise a day.
From my experience it's just easier to eat less than exercise enough to loose weight. I had my biggest weight loss while eating less and cycling more. The cycling was easier to do for hours at a time so I could contribute to a calorie deficit.
Speaking of calorie deficits I propose that regardless if it is from exercise or eating less your body will adjust some to compensate. For some it compensates more than others which is why it appears easier for some to loose weight than others.
I just don't buy it. I certainly have gained weight doing marathons. People do have a tendency to give themselves permission to eat more if they exercise. Exercise is often appetite stimulating and makes one lazy the rest of the day. Also estimates of energy expenditure are notoriously inaccurate.
The thing that makes me think that the constrained energy model is true is how my brain works after a long run. I’m just not up for tough mental work like writing or reading complex stuff even though I didn’t have to think that much while running. Since the brain needs a lot of energy, could that be part of this?
Absolutely - but I think that gets to the difference between the behavioral vs. metabolic constraint part of the argument. Which is it?
Is this chiefly a shot across the bows of Herman Pontzer’s work on metabolism (as detailed in his book ‘Burn’)? Any response from his team so far?
Encouraging news for those of us who’d like to think our efforts to exercise are contributing something positive to our body composition goals, even if we know diet is the bigger influence.
It’s one study among many and it’s certainly not the nail in the coffin of the constrained model. Pontzer’s and team also have extensive data (and longer term) that would push back against these findings. He actually responded to me on X!
“This was a 10 day study. Not sure why anyone would think these changes would happen that quickly or necessary show up in RMR. Our work (which they cite but don’t get quite right) suggests the changes take months and don’t always show up in RMR.”
Hmmmm, so it could be a case of ‘it’s not either, it’s both’, depending on time frame and frequency of exercise perhaps? I look forward to watching the debate progress.
Check out ‘Burn’ by Herman Pontzer!
Yes I’ve read it, it’s fascinating 😊
Experience of one here. The model is additive. However as weight is lost energy expenditure goes down through simple physics.
It seems to me that, just as the body expends less energy for a given effort in a conditioned athlete, that same body will expend less effort in maintenance at rest. The heart, lungs (diaphragm), and even skeletal muscles get more efficient delivering and utilizing oxygen whether exercising or resting. Using that as a basis (hypothesis) for experiments (studies) should provide more insight than a "compensatory model" hypothesis - in my opinion.
Incredible insight there Raymond. The question would then be how much more efficient we become—enough to really move the needle on metabolism?
On the contrary, if someone gets fitter and improves muscle mass, EE might increase.
Thanks for that review-- I think the compensatory model needs to be challenged. The primary driver of resting energy expenditure remains lean body mass, and chronic exercise rarely fails to increase or maintain LBM. I do feel that comensatory NEAT and food intake can change considerably in response to exercise sessions, but they are independent of resting energy expenditure.
NEAT and food intake are without a doubt the two biggest contributors here (both in a positive and negative direction).
Brady - nice job as always. I couldn't help but wonder if there's an efficiency element involved in the results? In other words, as I become more fit, EVERYTHING becomes easier - "costing" the body less for each activity performed. It seems that would account for the reduced metabolic cost? I couldn't tell if the researchers noted that possibility?
Wow - I’d never thought of that Brad. Probably something to it, but I would be curious how many calories are “saved” when one’s efficiency improves. My speculation is it wouldn’t be major.
Would this not be easy to demonstrate for someone that uses a power meter on their bike? Faster with the same power or less power for the same speed so long as their weight stayed the same. Unless your body just gets better at converting the calories into power at the pedal.
The couch after the long run as behavioral compensation in action made me laugh because it's true. Great walkthrough!