Lifting weights while fasting?

I start my fasts around 6 pm. It’s hard to squeeze a workout in before that.

What’s the effects of working out while fasting?
What if I recover from my workout using pure protein powder? Does that count as breaking the fast? Should I skip this?

There’s benefit to working out as it speeds up the process to ketosis and what not.

I have no problem working out 12 or 36 hours into a fast. Only time I’ve run into trouble is when I get 4 or 5 days into a fast.

There are no major downsides or upsides to training while fasted in most people when it comes to energy expenditure, the exclusion being if you feel depleted, which is common when you’re starting fasting. Most downsides will be dependent on your personal goals, such as building muscle mass and hitting new PRs while training. So long as your diet is in check with the correct macros during your eating periods, you can still see improvements in muscle and strength, just at a slower rate than a continuous eating diet. Keep in mind, the longer you’ve consistently fasted the better your energy will get in time with your training.
Using protein powder is going to break your fast. Soon as you ingest it your body is going to start trying to break it down. For recovery from exercise I highly recommend any sort of electrolyte drink (make sure it is 0 cal) or powder. Even something simple as adding salt to your water can majorly help with recovery. I personally use LMNT when I fast as it has a large serving of Sodium, potassium, and magnesium. However, they are expensive.