Context, I woke up ill this morning and ended up vomitting. I realised that I was vomiting my dinner from 13 hours previous!
This got me questioning where my body was getting energy from, how exactly energy gets ‘in’ to the body after eating, and how is food from so long ago largely undigested?
My very limited understanding is Food goes in acid -> food dissolves, undesired/undigestable expelled as waste. How does the ‘good stuff’ go from particles in the stomache acid into usable energy/resources?
In: Biology
Lurking. My understanding is that food’s constituents are broken down by chemicals in your stomach into their simplest forms. Most food is held together by relatively weak bonds.
A good answer should mention cellular respiration, the keeps cycle (citric acid cycle), and ATP. Oxidation of food (electrons flowing into oxygen molecules) is ultimately what provides the energy for ATP synthesis.
There will probably be some good answers on here.
It’s been a long time since I’ve studied this and I’m sure someone with in-depth knowledge will be along to provide details, but the highest-level gist of it is that your body breaks down food into progressively smaller and easier-to-handle bits (using both physical processes, like chewing, and chemical processes, including the actions of saliva, stomach acid, bile, and enzymes) until it gets to the point where the useful molecules can be shuttled through the walls of your small intestine and enter your bloodstream (and to an extent the large intestine, but its #1 job is absorbing water IIRC). The small intestine is lined with little finger-like protrusions to maximize contact area with the food matter to help this process work.
From there, your cells have several metabolic processes that convert those food-derived molecules into different molecules (ATP) that function as energy storage containers. Those get stored within your cells, and then when your body needs energy, they get fed into other chemical reactions that power the work (together with the oxygen that you breathe in).
All the chemical components of the food that aren’t useful for converting to ATP or something else the body can utilize will continue to pass through the gut and eventually be discarded in the form of a bowel movement.
As to why 13-hour-old food would be largely undigested… well, digestion takes a fairly long time (anywhere from 24 to 72 hours, according to a quick Wikipedia check).
Latest Answers