Anthropology P380: Protein and Fat
So, you're a primate looking for energy -- simple sugars are a good way to go, but still only provide 4 kcal/g. You don't have a gut specialized to digest cellulose. What are your other options?
What is a "calorie" ? The physiologically available or metabolizable energy yield of foods actually consumed. One kilocalorie (kcal) is the amount of heat energy necessary to raise 1 kg of water from 15 to 16 degrees Celsius.
How does a body derive energy from food? Energy is stored in molecular bonds in nutrients... degrading the compounds = breaking the bonds and you release the energy ... either as heat (in testtube), or can be captured in the metabolic pathway into another form for physiological use (or storage as body fat or ADIPOSE TISSUE). Some tissues, such as brain tissue, can only metabolize glucose as an energy source, and cannot acquire energy from other molecular forms (such as the VFAs volatile fatty acids produced by bacterial fermentation)
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Last updated: 10 September, 1999
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