There is nothing wrong with aspiring for more than that (I do too!).
My point was that to actually really retain all of the muscles after losing 50 pounds the answer is obvious - wear a 50 pound weight vest all day, every day (otherwise, it is a lot of gym time).
What retaining that muscle is not (from what I have heard on podcasts etc.) is simply the consumption of protein (although many supplement companies want you to believe that).
What I hear is that your body does not want to retain highly metabolically active muscle it does not need.
So, upon moving from say 200 pounds down to 150 pounds - it is great to try to strength train regularly to be in the top 10 or 20% of 150 pound persons in terms of strength.
But thinking you can eat your way into keeping the 200 pound person’s strength is probably spurious thinking.
Same with starting weights of 300 or 400 pounds. A 150 pound person would have to squat a 250 pound barbell every time the 400 pound person got out of his or her chair - don’t think so.
The person that tipped me off to this effect worked at testing body fat using the dunk tank. I was complaining that even though I worked out very hard, I was still losing lean body mass. He pointed out my overall weight had dropped 30 pounds so that was 30 less pounds for every movement (workouts and getting in/out of desk/bed/car etc.) which simply did not support the previous amount of muscle I had (which was only necessary when I was at a higher weight).