I use pyramex i-force goggles which the double lenses system prevent fog.
In cold weather i add a face cover to prevent fog furthermore.
To do that I use a cheap stair gripper made in plastic (5$-10$). I cut a square and cut a goggle shape in it. So i end up with a square with a hole shaped like goggles. I put this square on my face and my goggles above it. I use it when needed and remove it when not.
It's pretty similar to the face cover used in polar expedition.