“Does anyone know about the GM-CSF protein?”
Yes, it is an internal hormonal stimulant for white blood cells.

“Is this something you can increase in your body through food?”
No

“I’ve read that having this protein can help decrease inflammation caused by the flu”
No

“I’m curious to know if you can get this protein in any food?”
No

“Is is something that even comes from food”
No

“so thought I’d ask you brain boxes here”
Wikipedia is your friend