Why does eating make you feel better?
During the meal in the human body is released the "hormone of pleasure" - dopamine. And its level rises twice: when we start to eat and when the meal is already in our stomach.
Since an increase in dopamine levels is a reward for an action, a person feels pleasure and seeks to do that action again. In addition to eating, dopamine rises during sex and sports. This is why dopamine is not just about pleasure.
In addition to dopamine, the body produces another joy hormone, serotonin. It is known that if your body produces enough serotonin, you will feel more alert and cheerful.
Unlike dopamine, serotonin is produced by the gut, not the brain. In addition to its possible effects on mood, the "joy hormone" regulates digestion, sleep, and is responsible for blood clotting and bone strength.

So where does our body get its raw material for the production of the pleasure and happiness hormones?
For example from the following foods: oily fish such as tuna and salmon; turkey and chicken; eggs; greens such as spinach; milk; soy products such as tofu and soy milk; nuts and seeds.

So why shouldn't our eat foods that are high in serotonin right away? It's because the serotonin from food doesn't go directly to the brain.

Why do we feel sleepy after a meal?
Have you ever had one of those moments when you're happier after a big, filling meal and you still feel sleepy? That's because foods which are hormones of pleasure and happiness increase the production of the sleep hormone melatonin. So, in addition to food, your body produces it in the evening when it gets dark.
You may also feel drowsy and lethargic due to increased levels of adenosine: the longer you stay awake, the more of this substance is stored in your brain. Caffeine helps to get rid of its effects, which is why we feel awake after tea or coffee.