Cooking meat has much more to do with breaking down some of the less digestible parts of the food.
For example, http://www.ncbi.nlm.nih.gov/pubmed/17827047 says "For meat, cooking compromises the structural integrity of the tissue by gelatinizing the collagen. Hence, cooked meat should take less effort to digest compared to raw meat. Likewise, less energy would be expended digesting ground meat compared to intact meat. We tested these hypotheses by assessing how the cooking and/or grinding of meat influences the energy expended on its digestion, absorption, and assimilation (i.e., specific dynamic action, SDA) using the Burmese python, Python molurus."
That abstract concludes "We found cooking to decrease SDA by 12.7%, grinding to decrease SDA by 12.4%, and the combination of the two (cooking and grinding) to have an additive effect, decreasing SDA by 23.4%. These results support the hypothesis that the consumption of cooked meat provides an energetic benefit over the consumption of raw meat."
> Half the time the sweet potato or meat was presented raw, and half the time cooked; half the time it was also pounded and half the time unpounded. ... For both meat and sweet potato, Rachel found that when the food was cooked the mice gained more weight (or lost less weight) than when it was raw. Pounding had very little effect.
> We suspect that there are two major reasons for cooked beef providing more calories than raw beef. In cooked beef, the muscle proteins, like the sugars in cooked starch, have opened up and allowed digestive enzymes to attack their amino acid chains. Cooking also does this for collagen, a protein that makes meat difficult to chew because it forms the connective tissue wrapped around muscle fibers. However, we do not know the exact mechanisms.
Neither mention killing off bacteria, which makes sense as 1) meat doesn't enter the bloodstream but only its digestive products, and 2) stomach acids kill most of the bacteria.
> The positive energetic effects of cooking were found to be superior to the effects of pounding in both meat and starch-rich tubers, a conclusion further supported by food preferences in fasted animals. Our results indicate significant contributions from cooking to both modern and ancestral human energy budgets. They also illuminate a weakness in current food labeling practices, which systematically overestimate the caloric potential of poorly processed foods.
For example, http://www.ncbi.nlm.nih.gov/pubmed/17827047 says "For meat, cooking compromises the structural integrity of the tissue by gelatinizing the collagen. Hence, cooked meat should take less effort to digest compared to raw meat. Likewise, less energy would be expended digesting ground meat compared to intact meat. We tested these hypotheses by assessing how the cooking and/or grinding of meat influences the energy expended on its digestion, absorption, and assimilation (i.e., specific dynamic action, SDA) using the Burmese python, Python molurus."
That abstract concludes "We found cooking to decrease SDA by 12.7%, grinding to decrease SDA by 12.4%, and the combination of the two (cooking and grinding) to have an additive effect, decreasing SDA by 23.4%. These results support the hypothesis that the consumption of cooked meat provides an energetic benefit over the consumption of raw meat."
For another example, see http://blogs.discovermagazine.com/crux/2011/12/08/why-calori... :
> Half the time the sweet potato or meat was presented raw, and half the time cooked; half the time it was also pounded and half the time unpounded. ... For both meat and sweet potato, Rachel found that when the food was cooked the mice gained more weight (or lost less weight) than when it was raw. Pounding had very little effect.
> We suspect that there are two major reasons for cooked beef providing more calories than raw beef. In cooked beef, the muscle proteins, like the sugars in cooked starch, have opened up and allowed digestive enzymes to attack their amino acid chains. Cooking also does this for collagen, a protein that makes meat difficult to chew because it forms the connective tissue wrapped around muscle fibers. However, we do not know the exact mechanisms.
Neither mention killing off bacteria, which makes sense as 1) meat doesn't enter the bloodstream but only its digestive products, and 2) stomach acids kill most of the bacteria.
That second paper is http://www.pnas.org/content/108/48/19199.abstract .
> The positive energetic effects of cooking were found to be superior to the effects of pounding in both meat and starch-rich tubers, a conclusion further supported by food preferences in fasted animals. Our results indicate significant contributions from cooking to both modern and ancestral human energy budgets. They also illuminate a weakness in current food labeling practices, which systematically overestimate the caloric potential of poorly processed foods.