Hi, I am trying to gain weight so i eat a lot. But i always wondered, when exactly does excess food turn into muscle, fat or other stuff in the body? Where and how does that happen? All I could find on the web is just “you eat stuff and ya da ya da it turns to fat!” Lol.
thanks for answers.
In: 1
Short answer: as soon as you eat it.
Okay so think of it this way: your body is built out of molecules which function like little Lego building blocks. Your body uses those Lego bricks puts together these bricks in different combinations to build the various things it needs to build. Digestion is the process of turning food into those little building blocks so they can be used when and where they are needed.
In terms of contributing to you mass, the building blocks are adding mass as soon as you eat them. Whether they are already assembled into something or are still waiting to be used, their mass is the same. So, once you have pulled the Lego pieces out of the rest of the stuff you can’t absorb (thanks intestinal tract!) you have that mass.
Food gets broken down by enzymes in your mouth, stomach, and small intestines. As it moves through these structures, it gets mashed up into something called chyme. This allows your intestinal cells to absorb the different nutrients that compose food, i.e sugar, fats, proteins. This influx of nutrients into your blood stream stimulates insulin, among other hormones. Insulin tells your cells to open their doors and allow nutrients to flow into them. Sugar gets used for energy, but excess sugar gets turned into fat for storage. Amino acids from protein gets used for building things in cells, but it can also get turned into sugar in the liver if it needs to be. Fat gets stored for later. This is where the weight comes from. If you balanced your caloric intake exactly with your energy needs, you wouldn’t gain weight. Now this is largely ignoring weight from water consumption and from the “leftover” indigestible components of food that you poop out.
Basically all the time everything happens at once. You burn and store fat simultanously, at the same time youre building muscle if needed (they needed to be stimulated) and if you have protein. If youre not gaining fat then youre burning more energy than you provide to your body
As soon as it’s made it weighs something. If you eat a certain weight of something, you are now that much heavier. Then your body digests it, but not all of it, so you pee and poop some of it out. You use the rest and store some as fat. At this point it’s fully incorporated into “you”.
>When exactly does food turn into weight?
As the top answer says: When you eat it. If you pick up and eat a 1lbs watermelon slice, you weigh 1 bls more, immediately. It’s 90% water, so 0.9 lbs of that gets pulled out by the intestines, take a ride through the bloodstream, gets used for all sorts of stuff, collects some junk, and most of it will eventually get pulled out by the kidneys and pissed away. Some water is kept in cells. You’re mostly water.
The other 0.1 lbs which is food has a different lifecycle.
> when exactly does excess food turn into muscle, fat or other stuff in the body?
The intestines pull out the food bits as all the separate components of food: sugar, starch, protein, yadda yadda yadda. It all goes into the bloodstream. Bunch of stuff, each with a slightly different fate. The sugar can get sucked up by cells, tossed into the furnace, used to make ATP energy, which is used to do stuff. Out of the furnace the burnt remains are CO2 which go back into the blood and eventually out to the lungs. Starch has a fun cycle to get turned into sugar. All that has a fun cycle of sythethesising (creating from scratch) protein, or you can just take the raw protein straight to go build structures like muscles or messages in the horrifically complicated protein expression system.
There’s pathways to make (synthesize) a lot of the stuff you need out of the stuff you have. If you have a lot of excess energy in the bloodstream (starch, sugar, ATP) then long-term energy storage is made: Lipids. Fat cells store these guys for when you need energy for later.
All in all all these pathways are horrifically complicated and summed up into: Metabolism. The body’s chemical refinery. Breaking down stuff and building it back up. There’s a lot of hand-waving and generalization like you noticed because the details are really bloody complicated. Really, [nothing about this page is simple](https://en.wikipedia.org/wiki/Anabolism) enough for a 5 year old. So the story we tell at elementary school levels is “the body makes fat from excess calories”. Which is true, but skips over a lot of detail.
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