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So is your rebuttal to Pontzer et al that it doesn’t match your personal experience?

by alecst 2y ago

paulpauper 2y ago
My own experience matches closer to Potzner's work. I see some initial loss on the after exercising but the rebound is really fast. Perhaps if you keep it up everyday there can be some long-term weight loss but it will not be continuous, and if you stop the weight will come back fast.
- throwaway22032 2y ago
  Isn't that kind of like saying that the tooth decay will come back real quick if you stop brushing your teeth? Most people need to supplement their activity with exercise nowadays because otherwise their lives are very sedentary. It's a forever thing, unfortunately for those that don't enjoy it.
- sudosysgen 2y ago
  Your weight is an equilibrium between calorie intake and caloric expenditure. Increased weight increases baseline expenditure, hence the equilibrium. If you stop exercising, but keep the same caloric intake as before, yes, it will rebound really fast, because the equilibrium point will stay the same. If you want to move the equilibrium, you either need to do the exercise regularly forever, or reduce your caloric intake, or build significant amounts of muscle (fat free body mass) to increase your baseline. expenditure
mint2 2y ago
So we’re focusing on the anecdotal part to ignore the part where I point out the naive reading of his conjecture literally defies thermodynamics? I pointed out it’s literally impossible for it to work for a subset of the population. Over a hundred thousand endurance athletes in just the USA would have to literally defy the laws of thermodynamics for the naive reading to work. I can see why the question ignored that and focused on the personal story that went along with the hard facts and stats.
- alecst 2y ago
  Pontzer's work isn't about napping. It's about your body having a set point for how many calories it burns, independent (up to a factor of +/- a few hundred calories) of how much exercise you do. For most people this is true, as their work shows. It may not be true for extreme athletes. I don't think Pontzer's team of dozens of people working over ten years misunderstood basic thermodynamics. Their work clearly points to "compensation" -- the body making up for energy it burned during the day by gently lowering the metabolism later on. Saying "burning 600 calories now means burning 600 less later" gets the point across. It's pretty much on the money for some people. For others compensation may not be total. I guess I'm not really sure where your beef is.
  - mint2 2y ago
    For hundreds of thousands of people it’s not true. That is not an exaggeration in numbers. Handwaving away large numbers data points that disprove a theory is not how science is supposed to work. And as we have seen in this thread, the lack of clarity on the nuance discourages people from making exercise. Over simplifying it to 600 burned, 600 saved later is harmful and also inaccurate. (and yes More inaccurate than my loose choice of saying nap which you pointed out that led you to the wrong conclusions on my understanding, please consistently apply that critical standard)
    - rojeee 2y ago
      Also an endurance runner and read Pontzer's book. I do enough running for my wife to get pissed off! I agree with you that there's definitely more work which needs doing to understand metabolism in the context of endurance athletes. I don't think his work is outright nonsense though. Here's something to think about... I ran 21 km yesterday, in zone 2, in a fairly glycogen depleted state. That was about 4:30min/km for 21km, with 600m of elevation - about 1500kcal of energy. I didn't eat or drink anything throughout the run. I'm a big nerd, so I took a lactate sample at the end. I didn't hit the first ventilatory threshold for the whole run and that indicates I'm burning a large proportion of fat compared to a normal person (and probably a normal recreational runner). Afterwards, I ate a banana and had a couple of spoons of peanut butter + honey. A few 100kcal. Fast forward to the evening. I didn't eat any more than I usually would do if I had a few days off running. I went on with my day as normal and recovered fine the next day. I didn't feel hungrier than usual. Fairly standard. My body is well adapted to this kind of exertion. I think my body is quite efficient at doing every day things. I don't get out of breath walking up stairs, for example. Maybe it's fair to say I'm more energy efficient than a regular person. Perhps, I don't need to eat any more than usual immediately after running because I'm burning a high proportion of fat and my metabolism is quite efficeint anyway. Someone who has a poor aerobic system wouldn't be capable of doing that. They'd likely be running at a much higher heart rate and bonk after 10km having not eaten any carbs the day before. They'd also likely need to eat a huge bowl of pasta afterwards just to feel OK. I suspect this person would feel like crap for the rest of the day (maybe even multiple days... Imagine.. they've likely just done a 10km at VO2max untrained) and I could completely imagine them having a nap or watching TV for the rest of the day as they'd have no energy to do anything else. Their bodies are not adapted to this kind of exertion. They are not efficient. Their body needs to rest to get back in equilibrium. The energy requirement is the same in both cases but it comes from a different source. In my case the high fat oxidation is acting as a battery/buffer. In the average person, those fat stores are not really accessible when doing anything more than sitting or light walking. Both examples are in equilibrium but present in different ways.

So is your rebuttal to Pontzer et al that it doesn’t match your personal experience?

by alecst 2y ago

So is your rebuttal to Pontzer et al that it doesn’t match your personal experience?

My own experience matches closer to Potzner's work. I see some initial loss on the after exercising but the rebound is really fast. Perhaps if you keep it up everyday there can be some long-term weight loss but it will not be continuous, and if you stop the weight will come back fast.

throwaway22032 2y ago
Isn't that kind of like saying that the tooth decay will come back real quick if you stop brushing your teeth? Most people need to supplement their activity with exercise nowadays because otherwise their lives are very sedentary. It's a forever thing, unfortunately for those that don't enjoy it.
sudosysgen 2y ago
Your weight is an equilibrium between calorie intake and caloric expenditure. Increased weight increases baseline expenditure, hence the equilibrium. If you stop exercising, but keep the same caloric intake as before, yes, it will rebound really fast, because the equilibrium point will stay the same. If you want to move the equilibrium, you either need to do the exercise regularly forever, or reduce your caloric intake, or build significant amounts of muscle (fat free body mass) to increase your baseline. expenditure

mint2 2y ago

So we’re focusing on the anecdotal part to ignore the part where I point out the naive reading of his conjecture literally defies thermodynamics? I pointed out it’s literally impossible for it to work for a subset of the population. Over a hundred thousand endurance athletes in just the USA would have to literally defy the laws of thermodynamics for the naive reading to work. I can see why the question ignored that and focused on the personal story that went along with the hard facts and stats.

alecst 2y ago
Pontzer's work isn't about napping. It's about your body having a set point for how many calories it burns, independent (up to a factor of +/- a few hundred calories) of how much exercise you do. For most people this is true, as their work shows. It may not be true for extreme athletes. I don't think Pontzer's team of dozens of people working over ten years misunderstood basic thermodynamics. Their work clearly points to "compensation" -- the body making up for energy it burned during the day by gently lowering the metabolism later on. Saying "burning 600 calories now means burning 600 less later" gets the point across. It's pretty much on the money for some people. For others compensation may not be total. I guess I'm not really sure where your beef is.
- mint2 2y ago
  For hundreds of thousands of people it’s not true. That is not an exaggeration in numbers. Handwaving away large numbers data points that disprove a theory is not how science is supposed to work. And as we have seen in this thread, the lack of clarity on the nuance discourages people from making exercise. Over simplifying it to 600 burned, 600 saved later is harmful and also inaccurate. (and yes More inaccurate than my loose choice of saying nap which you pointed out that led you to the wrong conclusions on my understanding, please consistently apply that critical standard)
  - rojeee 2y ago
    Also an endurance runner and read Pontzer's book. I do enough running for my wife to get pissed off! I agree with you that there's definitely more work which needs doing to understand metabolism in the context of endurance athletes. I don't think his work is outright nonsense though. Here's something to think about... I ran 21 km yesterday, in zone 2, in a fairly glycogen depleted state. That was about 4:30min/km for 21km, with 600m of elevation - about 1500kcal of energy. I didn't eat or drink anything throughout the run. I'm a big nerd, so I took a lactate sample at the end. I didn't hit the first ventilatory threshold for the whole run and that indicates I'm burning a large proportion of fat compared to a normal person (and probably a normal recreational runner). Afterwards, I ate a banana and had a couple of spoons of peanut butter + honey. A few 100kcal. Fast forward to the evening. I didn't eat any more than I usually would do if I had a few days off running. I went on with my day as normal and recovered fine the next day. I didn't feel hungrier than usual. Fairly standard. My body is well adapted to this kind of exertion. I think my body is quite efficient at doing every day things. I don't get out of breath walking up stairs, for example. Maybe it's fair to say I'm more energy efficient than a regular person. Perhps, I don't need to eat any more than usual immediately after running because I'm burning a high proportion of fat and my metabolism is quite efficeint anyway. Someone who has a poor aerobic system wouldn't be capable of doing that. They'd likely be running at a much higher heart rate and bonk after 10km having not eaten any carbs the day before. They'd also likely need to eat a huge bowl of pasta afterwards just to feel OK. I suspect this person would feel like crap for the rest of the day (maybe even multiple days... Imagine.. they've likely just done a 10km at VO2max untrained) and I could completely imagine them having a nap or watching TV for the rest of the day as they'd have no energy to do anything else. Their bodies are not adapted to this kind of exertion. They are not efficient. Their body needs to rest to get back in equilibrium. The energy requirement is the same in both cases but it comes from a different source. In my case the high fat oxidation is acting as a battery/buffer. In the average person, those fat stores are not really accessible when doing anything more than sitting or light walking. Both examples are in equilibrium but present in different ways.