I follow the Russian Sheiko powerlifting training plan, eating around 4500 calories a day. Not sure how my body would react to skipping entire days without eating. If I miss my second late night snack I wake-up famished.
You should try it. I predict you will be very surprised.
Not only am I able to complete a power lifting regimen (1.5 hours, squats, deadlifts, basic stuff) in a 16+ hour fasted state but I sometimes find myself having more energy to do the lifts than in a non-fasted state.[1]
In two years I have never needed to stop short a resistance workout due to lack of energy (or whatever I used to worry about before I tried it).
Yes, you will need to more carefully budget those 4500 calories over the non-fasted blocks of time - you'll still need those calorie inputs. I suggest nut butters and avocados but whatever works ...
YMMV.[2]
[1] This is also true for my aerobic running workouts, but to be fair, I cannot do my full blown wrestling workout (60 mins of training followed by 4-6 5min rounds) in a fasted state.
[2] Something I found very surprising as I aged into my forties is that I used to think my exercise regimen(s) were the significant factor in my metabolism and calorie usage. In reality, if you add up how many calories you use lifting weights for 1.5 hours or running 5 miles, etc., it's quite modest ... the major contributor to my very high metabolic rate was just background metabolism. I mention this anecdotally because if you have difficulty without meals it's instructive to really consider how much of that is due to the workouts (which burn a (relatively) small amount of calories) vs. your actual background metabolism. It also suggests that if you have a negative response to IF now, it's worth trying again in five years as your background rate will naturally drop - even if you maintain the same (or higher) athletic output.
What benefits are there beside increased energy? I don't have a problem with my energy levels on my current regiment, I could do more exercise to burn more off.
I'll bet it's not optimal for significant strength gains.
I think it's possible, however, and it's really just a calorie math problem: if you require X calories per day to acquire whatever strength or weight gains you just need to be sure to hit that within 8 or 6 hours.
Which might be challenging, from a digestive standpoint.
I think I use about 3000 calories per day and can get that in two meals (implying a 16 hour fast) without any trouble, but when I do a 24 hour fast (implying one meal) I need to be careful and selective about that one meal ... and I probably go into a net calorie deficit over a 48 hour period as a result...
I'm not sure how heavy you are but those are already advanced (elite?) level lifts assuming you mean a 1300lb B/S/DL total. Since you must have been training for a number of years now you're probably going to struggle to get stronger if you're not on a caloric surplus. I'm not an expert though.
My lifting weights go down by at least 10-15% if I haven't eaten anything that day. Tried lifting in the morning before breakfast - didn't go too well either, just put me in a bad mood because I felt too weak.
Also, I wasn't really proper fasting, just hungry because of skipping 1 meal.
Lots of people are exercising while fasted. Body builders, power lifters, and athletes across the strength/endurance spectrum. For things like camping or distance jogging, being able to start at 6:00 and go until 16:00 without food is a game changer.
And, no: people who are training fasted aren't training hungry... Their hunger chemicals dissipate after 20-30 min because they're fasted ;)