late valve timing will end in lean condition?

i don't whant to mix up the discussion with my other'' late timing- shifting relationship'', so i started another 3D:
i searched on the net but i did not get an answer: it's possible that a 1 tooth retarded inlet cam can result in a lean condition, wither plugs tips, exaclty as a lean carburetor setting do?

I don't see how that could happen.

I suppose if the intake cam was wildly advanced, some exhaust gasses could be blown back into the intake tract, causing a lean (diluted) mixture. For that to happen, I bet there would also be some piston to valve contact going on.