I think you are crazily optimistic about both the FDA and the ability to see any significant health effects from fake meat. Even my vegan friends have only been eating it for about a decade, and that doesn't strike me as enough time for e.g. discerning whether it is carcinogenic.

Among other things, sodium nitrate (included in the above description of fake meat) is, by itself, known to be more carcinogenic than red meat itself. But you don't see the FDA ensuring new foods don't use it.