Word Trick ( Followup vs Follow up )

Just like to share one trick to find out which is right? and which is wrong? Just use word "eat" instead of follow up or followup.

Follow up

 " The patient needs to follow up next week.


This sentence  makes sense with word "eat" if we use it instead of "follow up."

The sentence will be:  "The patient needs to eat next week."

Followup

 " The patient will come in for followup in a week."

This sentence does not make sense with word "eat" if we use it instead of "followup."

This sentence will be: "The patient will come in for eat in a week."