I am a weight lifter, and have been for 35 years to competition level in my youth,I have been a personal trainer also, I am 51 years old on intermitted fasting ( 16 hours fasting / hours feeding window )and I train 4 times a week as heavy as I can in the morning at 7.30am. I train in the morning in my fasting time, with only a cup a coffee taken 30 minutes before training with some MCT oil in it.
This is because apart from fasting I am on a ketogenic diet, which I have adapted to the training and that provides me with the energy I need from fats and allow me to build lean muscle mass at the same time, to do this you would need to teach your body to switch fuel source over a period of time, from carbs to fat. As I do not know your diet, to recommend something I would need to know is you are in ketosis, if you are overweight or want to lose fat as well as building muscle and if you have any medical history related to metabolic issues or diabetic.
In any case, for resting and recovery sake, which is when you grow, I would recommend you eat after training, not before, as during training you need energy, but is after training that you would use the protein and the other micronutrients to rebuild and recuperate.
This is a deep subject that would require more said and explained, but from here on, it would be more tailor made to the individual.