Why is that if you fall asleep hungry you still wake up feeling more or less fine?

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Why is that if you fall asleep hungry you still wake up feeling more or less fine?

In: Biology

Because first world „feeling hungry“ usually is just your body telling you „I‘m used to getting food at this time“, not „I‘m starving I need food.

When you‘re fasting the first days are the hardest because your body expects food at the times it got them the last few days. Once you haven’t eaten for two days your body calms down until you really NEED food.

Short answer – You still have plenty of blood sugar to last on, and sleep shuts down digestion. It takes a little time to start back up. Basically, you don’t know what hunger is

Long answer:

There are at least 4 stages of hunger

1- Stomach is empty, I would like some food.

2- Stomach/intestines are cleared out. Running on blood sugar so you better get food now.

3- Blood sugar is gone, converting fat and muscle to keep you alive. You better chase a small animal down NOW or you’re going to die. Not true, but thats what it feels like.

4- Fat and muscle are no longer supplying enough of what you need. On top of hunger you’re suffering physical and cognitive impairment from lack of nutrients. You are likely sustaining long lasting or even permanent damage to your body. Eventually your brain and heart will shut down and you die

It can take 4-6 hours to get to 2, depending on what you’ve eaten. Your blood and liver store ~24 hours of blood sugar. You can’t get a decent estimate of when you will progress to 4, but you will run low on vitamins, ect before you run out of fat and muscle. If you live in a developed nation its possible to never have gotten to 2, and likely you’ve never seen 3. In the unlikely event you see 4, a doctor would probably recommend an extended hospital stay

While you are asleep your body works to keep you alive and homeostasis up.

Your blood sugar levels are tightly controlled, when it drops you start producing hormones to tell you that you are hungry and hormones to break down it’s sugar and fat reserves to keep you alive.

While you are asleep it’s mostly growth hormone and cortisol that start lipolysis (fat breakdown)

It’s called neoglucogenesis!

To be very simple, you go to sleep with low blood sugar (feeling hungry).

(even if you go to sleep with normal levels of blood sugar this phenomenon will happen too, because during the night your glucose blood level will go down)

During the night, a couple of hours before waking up, cortisol will be released in your blood stream telling your liver to make some glucose through neoglucogenesis and release it into your blood, your glucose go up, you wake up not feeling hungry anymore !

Edit 1 : Glycogenolysis is the breaking down of glycogene into glucose activated mainly by glucagon and adrenaline

BUT, the amount of glycogene stored in your body is pretty low, once glycogene is depleted (and it will be during the night, or if you go for a run or whatever) neoglucogenesis (or gluconeogenesis) will take the relay to make glucose for your body

If you wonder how glycogene is made, this is how your body stores glucose, it does it after you’ve eaten, through GLYcogenesis activaded by insulin

Edit 2 : Your blood sugar might be to a normal level when you wake up, but you don’t have anymore Glucose stored in your body (all of it is essentially in your blood or have been used already)

You hate breakfast because you are not hungry, breakfast is important because the food you’ve eaten gives you glucose that is stored in the form of glycogene, for you to use it throughout the day, without noticing, to keep your blood levels normal

You feel hungry when a hormone named Ghrelin increase. It usually increase at your usual time of having meals. It’s a kind of reminder for your body to eat. But eventually the Ghrelin decrease by itself and waits for the next meal time to increase again. So you feel hungry because of the hormone not cuz you didn’t eat