Ok this may sound weird, illogical and funny!
But the day I eat Pizza with lots of cheese - I get a bad dream!!
Seriously - I have actually noted down the days I ate plain pizza and days I ate cheese pizza!
Dreams like I am having argument / big fight with someone OR I am threatening someone! etc
And 100% I have got a bad dream on the day I ate lots of cheese!
Sounds weird but proven for me!

i.e. food may have link with body and thinking?!