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Superstition? Astrology? I think you never took a physics class? Please check the law of conservation of energy[1]. A human being is an isolated system, to lo

by jazzyk 10y ago

Superstition? Astrology? I think you never took a physics class? Please check the law of conservation of energy[1]. A human being is an isolated system, to lose body mass, you need Energy Used > Energy ingested. We may not measure caloric values of food properly, and depending on our genetics and age our caloric expenditures/activity will vary. However imprecise, comparing caloric values of chips (150kcal/oz) and leeks (16 kcals/oz) should still tell you something. [1] https://en.wikipedia.org/wiki/Conservation_of_energy https://en.wikipedia.org/wiki/Conservation_of_energy

WorldMaker 10y ago
First of all, a human body is not an isolated system from a law of conservation of energy standpoint. A human body is a complex ecology of micro-organisms and chemical processes with different energy needs, storage solutions, masses. A human body is continually interacting with its environments including factors that we are just now starting to truly analyze such as the microbiome, which is the crux of the article referenced here. But that is beside the point, calories != energy (which is properly Joules now in SI system) on either side of the CICO scale, especially the "energy used" side. It's not just a matter of precision, calories are an approximation to energy at best. But if you want to argue that calories on the input side are still useful, I get that calories can sometimes be a useful first pass approximation, especially to numbers-minded software folks that like easy metrics, and there are plenty of examples where comparing two calorie numbers gives you a reasonable approximation of the comparative "weight" of foods. But there are also plenty of counter-examples: most Diet Sodas have less calories than their "non-diet" counterparts but the science doesn't seem to bear out that they are "healthier"; olestra chips had lower calories than other chips but were determined to be rather unhealthy to the digestive system and people gained weight eating them... Calories don't tell you anything about what is in the food or how the body will react to it. I get that as software-minded people we like nice easy metrics, but calories are not a good metric.
- jtuente 10y ago
  Now that was entirely pedantry. The microbiome isn't excluded from the law of conservation of energy either. Different microbiomes may process food differently, but it cannot extract more energy than is available. A calorie is a unit of measure of energy, specifically the energy required to increase the temperature of 1g of water 1C. The fact that it is inconsistent based on temperature and pressure doesn't invalidate its definition. It is approximately 4.184J. Your example of diet soda is completely off the point as well. A lot of poisons have 0 calories, that doesn't make them good diet food. Olestra is another bad example, because the rats in the experiment didn't gain weight from the olestra but from a feedback effect that resulted in further overeating. But you're right in that calories don't tell you whether something you eat is poisonous. Calories are a good enough metric, but they require regular reevaluation in order to make decisions.
  - WorldMaker 10y ago
    If we want to deal in over-simplifications, from the toroid simplification of the human body the microbiome is entirely external to it and the energy it extracts is way more important than the energy in "food". I think at this point we both have very different views of who is being pedantic and I don't think we are going to convince each other of anything.

by jazzyk 10y ago

WorldMaker 10y ago

First of all, a human body is not an isolated system from a law of conservation of energy standpoint. A human body is a complex ecology of micro-organisms and chemical processes with different energy needs, storage solutions, masses. A human body is continually interacting with its environments including factors that we are just now starting to truly analyze such as the microbiome, which is the crux of the article referenced here. But that is beside the point, calories != energy (which is properly Joules now in SI system) on either side of the CICO scale, especially the "energy used" side. It's not just a matter of precision, calories are an approximation to energy at best. But if you want to argue that calories on the input side are still useful, I get that calories can sometimes be a useful first pass approximation, especially to numbers-minded software folks that like easy metrics, and there are plenty of examples where comparing two calorie numbers gives you a reasonable approximation of the comparative "weight" of foods. But there are also plenty of counter-examples: most Diet Sodas have less calories than their "non-diet" counterparts but the science doesn't seem to bear out that they are "healthier"; olestra chips had lower calories than other chips but were determined to be rather unhealthy to the digestive system and people gained weight eating them... Calories don't tell you anything about what is in the food or how the body will react to it. I get that as software-minded people we like nice easy metrics, but calories are not a good metric.

jtuente 10y ago
Now that was entirely pedantry. The microbiome isn't excluded from the law of conservation of energy either. Different microbiomes may process food differently, but it cannot extract more energy than is available. A calorie is a unit of measure of energy, specifically the energy required to increase the temperature of 1g of water 1C. The fact that it is inconsistent based on temperature and pressure doesn't invalidate its definition. It is approximately 4.184J. Your example of diet soda is completely off the point as well. A lot of poisons have 0 calories, that doesn't make them good diet food. Olestra is another bad example, because the rats in the experiment didn't gain weight from the olestra but from a feedback effect that resulted in further overeating. But you're right in that calories don't tell you whether something you eat is poisonous. Calories are a good enough metric, but they require regular reevaluation in order to make decisions.
- WorldMaker 10y ago
  If we want to deal in over-simplifications, from the toroid simplification of the human body the microbiome is entirely external to it and the energy it extracts is way more important than the energy in "food". I think at this point we both have very different views of who is being pedantic and I don't think we are going to convince each other of anything.