system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does not eating, or being really hungry, cause headaches?
gpt
Hunger headaches are normally attributed to either:

\- a low blood sugar or/and

\- a muscle tension

Depending on a person effects of hunger may vary drastically (not everyone will even have a headache, affecting factor are vast and diverse).

A l*ow blood sugar* (or rather a quick fall of a blood sugar level as a result of hunger)  sometimes cause significant changes in a function of brain blood vessels, which cause a headache.

*A muscle tension* is known to be sometimes causing by a low glucose levels in blood. A severe hunger,  may cause a muscle tension in any acting muscle, including face muscles, muscles in the forehead and other parts of the head, which can be sometimes recognized by us as types headaches.