A variation of intermittent fasting that is geared towards those that workout/weightlift is called leangains which you can learn about at leangains.com and r/leangains. I have been doing it for over 2 years and I lift fasted. You may feel light headed the first few times you do it (so go lighter on weights) but you get used to it. I do squats and deadlifts fasted no problem.