I guess for the fast food orders there could be some insights with enough volume and associated data (time, frequency, location.)

If someone suddenly started ordering loads or boycotted that one that decided homophobia was the way to go or something you could sense political leaning.

You could get a sense of allergies or vegetarianism.

You may figure out payday

Could maybe get a feel for menstrual cycles

Could figure out someone’s route home

Family size maybe.

Probably more idk.