Is there a food to avoid as nf1 patient?

Not necessarily: Nf1 is the usual form of neurofibromatosis. There are lots of skins changes with cafe au lait spots, freckling, and soft nodules. No specific food is a problem unless you have other GI problems. If you have nausea and vomiting, you need more thorough evaluation.

No: Neurofibromatosis type 1 may never cause you any problems, or it may be very troublesome. It is difficult enough to have an illness like this without falling for somebody's made-up internet dietary advice. Ignore it. Your food choices won't impact your disease. Simply eat sensibly, avoiding most of the very sugary, very salty, and very greasy stuff.