A MRP is a meal replacement. Most here would probably suggest either Surge or Grow. The reasoning behind a MRP, I believe, is that it absorbs quickly, which is good if you’re going straight to work out. I wouldn’t want to eat much before a morning workout, especially legs, but you do need something. That’s why I stick with half of a MRP (20ish grams of protein, 10-15ish grams of carbs, minimal fat, and lots of other little “goodies”).
Some here ingest either slow-digesting proteins before bed or wake up in the middle of the night to take in some protein, as 6-8 hours is a long time to go without protein. Thus, another hour or two in the morning without protein would be even worse.
I would also expect carbs to be somewhat necessary for energy purposes. Many do cardio first thing in the morning on an empty stomach to take advantage of that fasted/glycogen depleted state. Lifting weights, I think, would be a different animal. While undergoing a process of essentially breaking down your muscles, I wouldn’t want to be in a fasted state - I would want my body to have some form of energy and protein reserves.
Personally, I would pass out from trying to lift on an empty stomach in the morning. I know others are different, but I just can’t do that.
As far strength gain from lifting in the morning, the experience with most seems to have been that it doesn’t provide as many gains as working out at a more “alert” time later in the day. I’ve been working out in the morning for the past few weeks, and my poundages are a little lower on some lifts. Part of that may just be me adjusting to an early morning schedule. On some lifts, I feel that the one rep strength is there, but the endurance is not. Squats kill me that time of the morning, though I feel I could come close to my regular 1RM.
If the poundages used in the morning are less for most people, then I personally wonder if there is any carryover. For example, if you can lift x pounds y times in the afternoon, but only .8x pounds y times in the morning, then if you increased your morning ability to .85x pounds for y reps, would that increase your afternoon performance? I don’t know what the common experience is with this.