Why does cooked food offer more energy by bite? Does the heat weaken the bonds making it easier for us to break down and digest ourselves or something?
you know the molecular principles behind digestion, yes? probably?? they’re still teaching that in high school, right???
well, in case you need a refresher, I’ll address meat specifically: the basic principle is that meat is FULL of useful proteins structures that your body would really like to take and use for its own bits, but there’s a slight problem that needs to be dealt with first!
these proteins are FUCKING HUGE.
each protein is a sprawling 3-dimensional molecular structure containing hundreds to thousands of individual atoms, much much too big and also not quite the right shape for your body to repurpose!
and you need to start that blood vessel resurfacing project NOW, the funds were approved LAST THURSDAY for chrissake.
fuckin’ contractors. never on schedule.
so what your digestive system does is break the proteins down into their component chunks, via a process called denaturing! the denatured protein loses its structure and unspools itself into a long ribbon, which can be popped apart and taken to wherever those individual proteins need to go in your body.
HEY ED, GET A MOVE ON! THOSE TAURINES NEED TO BE AT THE LIVER ASAP!
and this denaturing process is fairly energy-heavy, so your body is BURNING energy and materials to PRODUCE energy and materials, and just barely comes ahead of breaking even!
at least, if we’re talking about raw meat.
see, your digestive system denatures proteins through an expensive chemical system, but it turns out there’s a cheap, easy, and (almost) FREE alternative that will do the same thing, no enzymes needed!
heat.
heat denatures proteins by its very nature, and we can actually see the process happen if we pay attention!
transparent egg whites turn milky and opaque as their regimentally organized protein structures unspool and tangle each other into uselessness, and red pigment proteins in muscle fibers turn grey as their molecular structure changes so drastically that it reflects an entirely different spectrum of light!
if you’re a human being, you refer to this process as “cooking”.
so when humans first started chucking chunks of mammoth into the fire way back when, they found they could use the fire to pre-digest the meat into useable protein chunks that take WAY less energy for your body to do something useful with, resulting in a net energy gain in the digestive process even though no extra energy was actually added to the meat!
in conclusion:
FIRE GOOD.
thanks for listening to my TED talk.
I'm not an expert here, but there's a similar thing going on with plants. Except instead of protein, it's polysaccharides like cellulose. We can digest a few of them as delicious, delicious starches, but others can't be absorbed by the intestine, and wind up as dietary fiber.
A lot of herbivores have incredibly long digestive tracts to ferment those polysaccharides into something digestible (this is why cows have so many stomachs). Humans can do a little of that--that's why beans make you fart. It's the gut bacteria breaking down polysaccharides and releasing gas in the process. Pills like Beano contain an enzyme to break down the polysaccharides before the bacteria get to it.
Anyway, all that is to say that, given we can't break down cellulose like a cow can, and since plant cells are wrapped up in a shell of cellulose, cooking breaks down the cellulose that encases plant cells enough that we can get access to whatever is inside (like vitamins, or more delicious, delicious starches).
not to derail this but it’s posts like these with such easy to digest (sorry) and passionate explanations to scientific questions that pushed me into the science education field. we might rag on some of the science side of tumblr posts from 2014 but actually that shit fucking slaps and comes in handy when teaching “complex” topics to people. the way this post is written is how i teach.