I eat whatever I want (except I'm limiting dairy) whenever I want. The things you eat modify the taste of your milk, so you may see baby frustrated at the breast. I've heard that by exposing LO to a number of different "flavors" you may help them be less fussy eaters. But I'm not sure how important that is in the long run.
To actually make baby have digestive problems there has to be something that passes from you, through your blood and into your milk. (Caffine, dairy protiens, etc.)
Just thought I'd add that.