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  • This episode is supported by Skillshare.

  • Campfires need wood to release heat, cars need petroleum to move, and you need food to fuel every aspect of your life.

  • So what would happen to your body, right now, if you suddenly stopped eating food?

  • To understand what happens without food,

  • we first need to understand what happens when you eat.

  • It starts with the sun, who's energy is harvested by photosynthesis and plants

  • We then consume that stored chemical energy,

  • either directly from eating plants like a tomato

  • or by eating an animal like chicken that has eaten a plant like grains.

  • If we take a hamburger as an example, you absorb fats from the lipid-filled sauces, proteins from the beef patty, and carbohydrates from the starchy bun.

  • And it's your digestive system using processes like chewing, gastric acid, and enzymes to break the food into small enough molecules that you can then absorb into your bloodstream.

  • Any excess glucose is stored in the liver and muscles as glycogen while some are converted into fats.

  • you can visually see some of the fat stores in the pudgier parts of your body.

  • There are around 37 trillion cells in your body and you start to really

  • harvest the energy from your food in the mitochondria of your cells.

  • This is where glucose and fats have been broken down into Acetyl CoA

  • and now go through the citric acid cycle

  • where they're modified continuously to release tons of energy carrying molecules.

  • The energy from these molecules are then used to pump protons

  • into a layer of the mitochondria that becomes so dense with protons

  • they need to diffuse back into the less busy space

  • and do so by going through a protein called ATP synthase.

  • As a result ATP is created, the most important energy source in your body.

  • You use around 10 to the [power of] 25 molecules of ATP everyday.

  • When this ATP is hydrolyzed to ADP in your body,

  • the bond breaks releasing energy for things like electrons forming bonds

  • and essentially creating all aspects of your ability to live.

  • If you stopped consuming food, within 6 hours your body will be breaking down glycogen into glucose

  • and fat into acetyl CoA to keep your biological processes at work.

  • And this is quite normal, but after 72 hours,

  • your body will need to start breaking down protein in order to synthesize glucose from amino acids

  • otherwise your brain will starve.

  • This is because fats used for energy can't cross the blood-brain barrier.

  • With no vitamins and minerals being consumed, people might start to get sick within a week.

  • After several weeks of starvation, fat stores become depleted, and all that is left for energy is proteins.

  • At this point essential proteins for survival, like antibodies used to fight infection

  • or muscle proteins used for strength, are now being used to make glucose.

  • And this loss of protein leads to severe illnesses.

  • Death can come as short as 3 weeks to 70 days,

  • commonly from a heart attack due to the tissue degradation of the heart, diaphragm, and body.

  • A factor in how long you live is how hydrated you stay

  • and also how many fat stores you had to begin with.

  • Although it's pretty amazing to think that if you did stop eating today

  • you could potentially live for another 70 days,

  • but please, don't try this at home.

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This episode is supported by Skillshare.

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