not very much, however much you'd normally eat, and it takes about thirty minutes.
avoid spicy or pungent foods.
you can experiment with this yourself by paying attention to your own body through the course of a day.
sweat will also take on different scents. for me, drinking coffee makes my sweat smell really strong . .
Obviously, eating things like garlic, doesnt take very long before garlic is coming out of your pores. . .
Drinking a lot of water, eating neutral things like celery help 'clarify' sweat etc . . .
Even emotions!! strong emotions like fear, panic, anger, love . . all will change the way you smell.