Eli5:Why we get hungry after a while and why our body doesnt just use our stored fat?


And after how many hours or days our bodies use our stored fat?

In: Biology

(Probably really bad) your body doesn’t know that it has fat stored, it’s only thinking about how you need more food because you haven’t eaten in ages. The fat is still burning but your body only realised what’s in its stomach not what’s stored up in your cells so it wants more food

Your body burns carbohydrates before fat. When you feel hungry, your body is saying it needs more carbs. Let it go long enough and your body will switch to turn burning fat. This is the idea behind the keto diet.

Your body is like a prepper. It has some food in the fridge (carbs) and some in the basement (stored fat), and if the fridge is empty it panics even though there are edible things in the basement. The basement is for emergencies! Now, you’ll still go downstairs and get yourself some of that emergency food, but it makes you feel bad and worried about the future, so you go to the grocery store as soon as you can.

This is actually how I stay thin. If you try intermittent fasting, your body gets used to not having food to burn and does get into the rhythm of burning fat stores instead.

You actually use your stored fat all the time, as soon as insulin falls and glucagon rises (i.e. between meals) lipolysis kicks into gear.

Imagine your driving a looong way away. You know you can make it but only just. You have to drive carefully but the car is still going to ping and show you the reserve tank sign. But you know you can make it.

Your body is the same. It has a reserve tank that it can use BUT it still pings to tell you that the main tabk is getting low.

What is also very important is when you eat. Your body adapts to this. Say weekdays you eat at 7 AM everyday. Your body now expects fuel at 7AM, but it is saturday and you are being lazy or preoccupied, so no fuel, your body signals harder because fuel is instinctively important to it. I was on night shift and used to eat my last snack at 4 am. The 1st month after leaving night shift, I woke up every morning at 430 am with hunger pangs. It took me some zolpidem/ambien and another month to change my routine back.

What you should also know is, your body does not just need fuel but also proteins. This is why a lack of musculature is common in starved people, because you don’t need proteins just for gains, you need them for normal cell reproduction, red blood cell production, waste management, etc.
That is why proteins such as red meat, chicken, etc are so filling because our bodies know that if it doesn’t get any, it has to use muscles whoch compromises our ability to fight or flee.

Say your sitting in the woods by a fire with a small stack of wood. When the fire starts getting low, you have two options, throw on more wood or go out and get more fire wood. You can throw on more wood but if you run out of wood in the middle of the night you might end up in a seriously bad situation. It could be wet or freezing cold, you could get lost or trip and hurt yourself. So you know it’s better to go and get more firewood now, if you are able to. This is what your body is telling you “Hey if you can go get more wood now, that would be great. If not then that’s also fine I have some but I was saving it for later and I’m going to bitch and moan about you making me use it”

Humans evolved in conditions where food was not always available. And what food was available usually had few calories. So we evolved to eat as much high calorie food as possible whenever it was available. Our body’s default assumption is that we are about to be starving for a long period of time so we better stock up while we can.