Double paned ("thermal") lenses are the only sure fire way to rid yourself of fog problems. I can't for the life of me figure out why the tactical gear industry hasn't caught onto this. Maybe they make too much money suckering people into buying anti-fog sprays/solutions/gels that don't work. Paintball masks and even windows for your house are double paned for a reason. Trust in proven science, not half assed relabeling of the same crappy products over and over.
I've had a pair of thermal JT paintball goggles for about 10 years that have NEVER (no, not even a single time) fogged on me in the worst of Texas weather. Summer, winter, humid, sweating, raining, whatever, they have never fogged. Even exhaling on them won't make them fog. I own several pairs of single paned tactical goggles and I can say the exact opposite about them, they have NEVER been fog free during any period of extended use.