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If they were obese it's because they had a caloric surplus (I doubt it). The laws of thermodynamics applied then, as they do now.

by tjogin 14y ago

radio4fan 14y ago
If the body digested everything with 100% efficiency and didn't produce waste, and also treated all 'calories' equally, then I'd agree that thermodynamics tells us everything we need to know. But even people coming from the complete opposite end of the argument to the paleo crowd ("Eat more whole grains!") agree that the amount of heat produced by a substance when it's burnt in a calorimeter doesn't tell the full story about its potential for causing obesity.
- tjogin 14y ago
  Yes, fans of either reductionist fad diet of the day are all ignorant.
  - regularfry 14y ago
    Or not. I can be a fan of a reductionist diet without buying the party line on the mechanism by which it works.
kbenson 14y ago
I thought it was rather obvious I was looking for justification as to why you thought cavemen didn't have the luxury of caloric surplus. You already made it clear that you more than doubt they they had that luxury, you definitively said they did not. Again, the question is why?
- tjogin 14y ago
  I have no idea how cavemen lived, and it doesn't interest me all that much either, but my guess is that they weren't as sedentary and they weren't as proficient in the art of preserving food. Overall, it should have been quite difficult for most of them to create a caloric surplus, day after day. What I do know is that bodymass is lost and gained with deficits and surpluses of calories. Transient spikes in insulin and stuff like that are irrelevant. This is well established in nutritional science.
  - cromulent 14y ago
    There's quite a lot of research with gut bacteria now and the association with obesity. It's not as simple as caloric intake, it is also the balance of the gut bacteria. http://www.ncbi.nlm.nih.gov/pubmed/17183312 http://www.ncbi.nlm.nih.gov/pubmed/17183312
Selfcommit 14y ago
Your assumption about the laws of thermodynamics predicates that the "Energy out" part of the equation is not somehow effected by the type of "Energy in" (Adding wet sticks to a fire will not produce as much released energy as adding dry sticks or gasoline soaked sticks) The general argument about carbs or any food with high glycemic response is that these foods are like adding "wet sticks" to the fire. There's considerable science and anicdote to support this. If you're interested (And not simply not throwing around pithy sound bytes about physics) check out: Why we get fat (And what to do about it) By Gary Taubes (http://garytaubes.com/ http://garytaubes.com/) For some very compelling anicdotal evidence (That also supports some concepts of Paleo) check out http://www.reddit.com/r/keto http://www.reddit.com/r/keto
- tjogin 14y ago
  Taubes has been refuted so many times it's astonishing that anyone still cites him. Compelling anecdotal evidence is an oxymoron, especially when the scientific evidence to the contrary is so strong.
  - Selfcommit 14y ago
    I've seen some work contradicting him, but would be interested in seeing something refuting him. Your phrase "Compelling anecdotal evidence is an oxymoron" seems strange. If 5 people told me they saw my wallet outside, I'd be compelled to check, by anecdote, if I'd dropped it on my way in. Please show me your science.
- dalke 14y ago
  Your metaphor of adding wet sticks to a fire is flawed, from a thermodynamics argument. Assuming that the fire is large enough, it will dry out the wet sticks through evaporation/boiling, and the wood's total contribution to the heat ("energy out") will be unchanged. Now, of course for the people sitting around the fire, some of the heat that would be warming them up or used for cooking is instead used to force a phase change in the water, so it won't be as much "useful" heat, but that meaning of utility - which I believe is the one you want - is outside of thermodynamics. For what it's worth, "for some very compelling anecdotal evidence" of the thermodynamic approach, see The Hacker's Diet at http://www.fourmilab.ch/hackdiet/ http://www.fourmilab.ch/hackdiet/ , which uses the "Rubber Bag" model. Unlike the garytaubes.com web site, the entire book and supporting materials are available for free download. The basic premise is the thermodynamic "if you eat more calories than you burn, you gain weight; if you eat fewer calories than you burn, you lose weight." (See also 'Food and fact' where "The rubber bag view of the body and considering only the calorie content of food is obviously oversimplified." and some of the complications are mentioned.) I believe you are making a different argument, which is that you can't always measure the caloric impact of foods. Under the Hacker Diet, that makes little difference. It uses a feedback system based on weight trends rather than specific calorie counting. There's no need to know that oak combustion produces about 15MJ/kg and boiling water from room temperature takes about 3MJ/kg, because it only looks at 'is there enough heat'?

If they were obese it's because they had a caloric surplus (I doubt it). The laws of thermodynamics applied then, as they do now.

by tjogin 14y ago

If they were obese it's because they had a caloric surplus (I doubt it). The laws of thermodynamics applied then, as they do now.

radio4fan 14y ago

If the body digested everything with 100% efficiency and didn't produce waste, and also treated all 'calories' equally, then I'd agree that thermodynamics tells us everything we need to know. But even people coming from the complete opposite end of the argument to the paleo crowd ("Eat more whole grains!") agree that the amount of heat produced by a substance when it's burnt in a calorimeter doesn't tell the full story about its potential for causing obesity.

tjogin 14y ago
Yes, fans of either reductionist fad diet of the day are all ignorant.
- regularfry 14y ago
  Or not. I can be a fan of a reductionist diet without buying the party line on the mechanism by which it works.

kbenson 14y ago

I thought it was rather obvious I was looking for justification as to why you thought cavemen didn't have the luxury of caloric surplus. You already made it clear that you more than doubt they they had that luxury, you definitively said they did not. Again, the question is why?

tjogin 14y ago
I have no idea how cavemen lived, and it doesn't interest me all that much either, but my guess is that they weren't as sedentary and they weren't as proficient in the art of preserving food. Overall, it should have been quite difficult for most of them to create a caloric surplus, day after day. What I do know is that bodymass is lost and gained with deficits and surpluses of calories. Transient spikes in insulin and stuff like that are irrelevant. This is well established in nutritional science.
- cromulent 14y ago
  There's quite a lot of research with gut bacteria now and the association with obesity. It's not as simple as caloric intake, it is also the balance of the gut bacteria. http://www.ncbi.nlm.nih.gov/pubmed/17183312 http://www.ncbi.nlm.nih.gov/pubmed/17183312

Selfcommit 14y ago

Your assumption about the laws of thermodynamics predicates that the "Energy out" part of the equation is not somehow effected by the type of "Energy in" (Adding wet sticks to a fire will not produce as much released energy as adding dry sticks or gasoline soaked sticks) The general argument about carbs or any food with high glycemic response is that these foods are like adding "wet sticks" to the fire. There's considerable science and anicdote to support this. If you're interested (And not simply not throwing around pithy sound bytes about physics) check out: Why we get fat (And what to do about it) By Gary Taubes (http://garytaubes.com/ http://garytaubes.com/) For some very compelling anicdotal evidence (That also supports some concepts of Paleo) check out http://www.reddit.com/r/keto http://www.reddit.com/r/keto

tjogin 14y ago
Taubes has been refuted so many times it's astonishing that anyone still cites him. Compelling anecdotal evidence is an oxymoron, especially when the scientific evidence to the contrary is so strong.
- Selfcommit 14y ago
  I've seen some work contradicting him, but would be interested in seeing something refuting him. Your phrase "Compelling anecdotal evidence is an oxymoron" seems strange. If 5 people told me they saw my wallet outside, I'd be compelled to check, by anecdote, if I'd dropped it on my way in. Please show me your science.
dalke 14y ago
Your metaphor of adding wet sticks to a fire is flawed, from a thermodynamics argument. Assuming that the fire is large enough, it will dry out the wet sticks through evaporation/boiling, and the wood's total contribution to the heat ("energy out") will be unchanged. Now, of course for the people sitting around the fire, some of the heat that would be warming them up or used for cooking is instead used to force a phase change in the water, so it won't be as much "useful" heat, but that meaning of utility - which I believe is the one you want - is outside of thermodynamics. For what it's worth, "for some very compelling anecdotal evidence" of the thermodynamic approach, see The Hacker's Diet at http://www.fourmilab.ch/hackdiet/ http://www.fourmilab.ch/hackdiet/ , which uses the "Rubber Bag" model. Unlike the garytaubes.com web site, the entire book and supporting materials are available for free download. The basic premise is the thermodynamic "if you eat more calories than you burn, you gain weight; if you eat fewer calories than you burn, you lose weight." (See also 'Food and fact' where "The rubber bag view of the body and considering only the calorie content of food is obviously oversimplified." and some of the complications are mentioned.) I believe you are making a different argument, which is that you can't always measure the caloric impact of foods. Under the Hacker Diet, that makes little difference. It uses a feedback system based on weight trends rather than specific calorie counting. There's no need to know that oak combustion produces about 15MJ/kg and boiling water from room temperature takes about 3MJ/kg, because it only looks at 'is there enough heat'?