Philosophy of Food Fall 2018 Class Notes
Revision as of 00:19, 25 September 2018 by Alfino
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SEP 18: 1
SEP 20: 2
SEP 25: 3
Gastrpod, "The End of the Calorie"
- Sanctorio Sanctorius - 30year practice for weighing inputs and outputs.
- Antoine Lavasier — Guinea pig in coffee urn - we “burn” food chemically. Change in temperature of water the pig is in. 1st “calorimeter”. Axed in French Rev.
- Later defined by a german scientists (Favre and Silbermann in 1852 or Mayer in 1848) as: Amount of heat energy to raise 1 gram of water by one degree centigrade from 14.5 to 15.5 at sea level.
- We still use calorimeters......museum of calorimeters also. Visit to contemporary calorimeter. Converted walk in cooler. Implication that the woman with the sewing machine “made a mess”?
- Bomb calorimeter. You burn the food. Segment on how it works.
- Wilbur Atwater. Atwater values. USDA scientist. “Father of nutrition science” (Nestle likes him.). 4,000 food values. Method...omg. Potental energy (bomb cal value) - excretion = value. 4 cal/gram of carb or protein. 9 calories per gram of fat. (7 alcohol).
- Recent evidence about variability of calorie values — researchers repeating Atwater research, but using additional measures. David Baer and Bill Rumpler both work at the Food Components and Health Laboratory at the USDA-ARS headquarters, in Beltsville, Maryland. Check out Baer and his colleagues' papers on the difference between the calories on the label and those our bodies can extract for almonds and walnuts.b. “The food is free, but you have carry ...”. 5-6% off on tree nuts, 30% on almonds, 21% walnuts,
- Richard Wrangham is the author of Catching Fire: How cooking made us human. Harvard medical anthropologist. —
- First to show that cooking changes food to allow earlier digestion (small intestine) and greater calorie recovery. 40% for starch. Also cooked meat, peanuts. All research on mice (and pythons). Still hard to say what the variation will be for us. Maybe 20-40%. What about heat extrusion, also called Food Extrusion? (Used in cereals.). Industrial food might raise calorie levels relative to atwater values. That's a good thing, right? Or is it?
- Digression on Food Extrusion (based on Sp'17 course):
- Sarah Haley — scientist claiming counting calories didn’t work.
- CALORIES AND THE GUT MICROBIOME
- Peter Turnbaugh's lab at the University of California, San Francisco, promises "better living through gut microbes." In our conversation with him, we discussed this study on the effects that transplanting gut microbes from lean and obese twins had on the weight of mice. Further examples of the impact of microbes on energy balance can be found in this paper on one woman's weight gain following a fecal transplant, and this paper on how risperidone is associated with altered gut microbiota and weight gain.
- microbiota creates variation in calorie capture.
- 36:45. Sarah Hailey comment.
- CALORIE REPLACEMENTS?
- Susan B. Roberts is the creator of the satiety-based "iDiet." She has also done extensive research into the accuracy of calorie counts on menu labels. David Ludwig's book, Always Hungry?, also proposes measuring foods based on their satiety score. Adam Drenowksi's Nutrient-Rich Food Index is explained here.
- They acknowledge that we don’t have a better standard, but other methods might tell us more.
- DAVID WISHART AND METABOLOMICSDavid Wishart's research group is based at the University of Alberta. You can check out the Human Metabolome Project Database online here. And the Israeli study on personalized nutrition based on individual glycemic responses is available online here.
- WHY THE CALORIE IS BROKEN
- We wrote a feature article for Mosaic, the online publication of the Wellcome Trust, to accompany this episode. You can read it online here.
- THE CHEMICAL DEFINITION OF THE CALORIE
- In the episode, we say that a calorie is the amount of heat energy needed to raise the temperature of one gram of water by one degree centigrade, from 14.5º to 15.5º, at one unit of atmospheric pressure. This is accurate, but it is misleading, because throughout the rest of the episode, we are discussing a different kind of calorie—the kilocalorie, which is the amount of heat energy needed to raise the temperature of one kilogram of water by one degree centigrade. The kilocalorie is the number we see on our food labels and recommended daily allowances, but no one other than chemists actually calls it the kilocalorie. Instead, it has been shortened to "calorie" on labels and in everyday usage. Throughout our episode, we follow common practice by calling a kilocalorie a calorie, but then we mistakenly gave the definition of a true calorie without noting the difference. We apologize for any confusion!
- The University of Alberta's David Wishart offers us a glimpse of the future, in which truly personalized nutrition advice will evolve from the emerging science of how the chemicals in our bodies interact with all the different chemicals in the food we eat. And Susan Roberts, director of the energy metabolism laboratory at the Tufts USDA nutrition center, suggests an alternative unit as a replacement for the traditional calorie.