Huh???

That's not what the OP is saying.

Sometimes when I am nauseated, it's because I haven't eaten in too long. Other times when I am nauseated, it's because I ate something that didn't agree with me or I'm sick. It becomes difficult to tell which it is until you try eating something.

If eating something ends up improving the nausea, then it was because you needed to eat. If eating ends up making the nausea worse, it's because you're sick or ate something that didn't agree with you. You can see how this then becomes a dangerous game to play.

This is not "nausea regardless of state". This is nausea where you can't tell the cause without potentially making it worse.

Have you really never been in that scenario before?