eli5: Why do you feel less hungry the longer you don’t eat?


So when your body is expecting food and you don’t eat you obviously get those strong hunger pains, but why does that feeling begin to die down if you leave it for a bit?

In: 29

The feeling of hunger is extremely complex and differs a lot from person to person and changes over time. So we can not even start to understand how it all works together. What you are describing tends to be a common trait in humans. And it might have made people more able to withstand periods of hunger and fight through it to find more food. This would have made people more capable of bringing up their offspring to bring these genetic traits on. However we do see that the body is able to train itself to withstand instincts like this. If you rely on this to reduce your food intake without feeling hungry, for example by intermittent fasting, then the body will adapt by for example getting stronger symptoms of hunger breaking down your will to fast or preparing for the fast period by eating way more then it needs building big fat reserves.

Hunger is produced by a hormone that has a natural rhythm throughout the day, it’s not caused by your stomach being empty.

Edit : I’m totally wrong on what I wrote so I delete my mistake.

Each person is different in a “Can we even see the same colors” sort of way. It’s really complicated, but essentially the stomach sends a signal to the thyroid which releases hormones for metabolism. Hunger is a mix of physical signals and hormones.

The body is more aware of changes than absolute values. So it gets used to things until the next change ie. Hunger pang.

Eventually the system gets confused if the signal persists, but at that point you are looking at more starvation or thyroid problems. Most people never get to that point though.

Lots of people talking about the complexity of the hormones and brain signals and they aren’t wrong. But I think one other answer to your question when talking about a normally fed healthy individual is that the liver actually kicks out a source of sugar to help mitigate the low blood sugar we are experiencing. This is called gluconeogenesis. This temporarily relieves the hunger pang.