My goal is to burn body fat while keeping muscle mass.  I realize diet is going to have more of an affect on that than anything else.  But within the subject of diet lies some variables.  One of them is when you eat what.  Old school was always have a high protein meal immediately after working out.  It's always been said that's when your muscles are primed to soak up as many nutrients as possible.  But does that have any effect on burning body fat? I'm trying to maintain my intermittent fast by not eating anything earlier than 1:00 PM. But I work out first thing in the morning.  That means I don't eat anything for four or five hours after my workout.  Am I helping or hurting my progress?

Eat your protein, keep lifting, and get into a calorie deficit.

Timing probably doesn't matter much for the non-elite.

This. "Calories in, calories out" is responsible for the vast bulk of diet efficacy. Lifting fasted is not optimal for gains, but you can still build muscle without issue.

If fat loss is your main goal, prioritize whatever dieting strategy keeps you in a deficit. If you want to bulk or prioritize increasing athletic performance, your dietary needs need to be subordinate to your training. Recomping (adding muscle and losing fat) is easier the fatter you are. As you lean down, it becomes more necessary to choose one.

I have no idea where you stand now in terms of body fat, muscle mass, training experience, etc. But if what you're doing is bringing down your body fat percentage, I'd keep going with it until you get more or less where you want to be. Then worry about changing things to optimize muscle building. A lot of guys worry about getting enough calories and protein to grow and never lose any fat.

You tell us.

Are your fasted workouts as intense in terms of reps and weight as workout that you had fueled up for?
I would suspect that they are not, but only you can know for sure.

For 20-30 minutes after training, the muscles are more efficient taking blood glucose and storing it as muscle glycogen.

This is primarily effective for endurance work, especially at higher intensities.  It also doesn't matter for someone training only once per day because after 18-20 hours there is no difference in muscle glycogen between the someone who consumes a post-workout meal and someone who eats normally.

I have never seen any studies about post-workout protein synthesis.

I'm 57 years old.  6'1", 260 lbs (Down from 275).  I'm guessing my BF% is somewhere in the 25% range.  I've got all the muscle mass I want and have no interest in adding more.  Just want to keep the muscle and strip off some of the fat. I'd like to get below 20%.

That's the thing, I started lifting seriously 27 years ago.  I've ALWAYS lifted first thing in the morning before any meals.  The only difference now is with intermittent fasting my first meal comes 4-5 hours after my workout instead of slamming a protein shake in the locker room immediately afterwards. But to answer your question no, I don't notice any difference.

If it's working, keep it going. The best (non steroid) way to hold onto muscle while you cut fat is to keep lifting heavy and make sure you get enough protein, while staying in a caloric deficit. Total lifting volume will probably have to be lower than if you were lifting and eating to grow.

Pretty much this.

I try and eat protein throughout the day. It helps me to get the macro goal in. If I wait until evening, there is no way to cram 150-200 grams of protein from meat in. And I can lift whenever you want, because I’ve eaten protein within an hour or two, and will eat more within an hour or two. My anabolic window is all awake hours.

See Leangains site and anything from Martin Berkhan re: intermittent fasting. I don’t think it’s a good idea unless you’re like 12%bf trying to cut further. I lift early morning fasted and always have. I’ve tried it the other way and hated it personally; guessing that’s from doing PT right out of the rack and eating after S,S,S.

@clubmanager1    My first guess would be Army.  But Marines would be a close second.

(I'm retired Air Force so I don't know how to spell PT )

Exactamundo!