Some argue that it's the BEST time to exercise. Check out Dr. Jason Fung. He's the newest IF guy on the scene right now. He just came out with a book, which I'm reading now, The Obesity Code. He also has a blog...which I can't remember the name of right now. Intensive Dietary Management? Anyway, I know he recommends working out, in general, in a fasted state. Not sure what he says about weight training specifically. But in my opinion, I don't believe it to be harmful, per say. I'm just not sure when you'd get the most benefit for the least amount of effort. I think Dr. Fung would say that a fasted state is optimal because that's when our ancestors would have been trying to spear an animal and then he'd use a bunch of science to back it up. 😉👍