I am dealing with this right now. The short response is the human body is remarkably adaptive and variable, and one weight loss method may not see you to your goal.
I lost 30 pounds by 500 calories fewer than my basal metabolic rate, with minimal changes to what I ate in terms of carbs, protein, fat, etc. or exercise. After that loss, I hit a plateau that I have been trying to bust for almost 9 months now. I have tinkered with eating more, eating less, exercising more, eating more protein and fewer carbs, sleeping more, and so on.
The best approach, in my experience, is to do the most sustainable thing FOR YOU that yields results. And when/if that stops working, start all over until you reach your goal.
I see the OP is discounting calories in-calories out due to “hormones, plateaus, starvation mode” and other factors-- don’t do this. You don’t even know if these will affect you. It’s more important to deal with the crap diet than the possible effects of factors which may or may not come into play.
In short, whatever scientific theories you choose apply or believe in, if your calorific intake is not less than your expenditure, you *will not *lose weight.
Many of the things you cite affect your calorific expenditure to a minimal amount. Not enough that it will make any difference to you.
Not noticeably. There might be miniscule differences, but he probably won’t perceive them unless he’s near is ideal weight where small differences are noticeable. He needs to reduce calories. If he does that* by* eating healther, all the better.
All that stuff is best left to the athletes who need to optimize perfectly. The initial 100lbs of weight loss makes those factors next to irrelevant.
Generally the higher protein diet will result in more weight loss because protein helps maintain a positive nitrogen balance, requires more energy to metabolize and suppresses hunger better than the alternative of keeping the current diet but cutting food by 25%.
Let me chime in again, as we go back to the original, blunt premise I offered: Eat fewer calories.
That’s it. Go with that first. You gotta stick to one or two things that have the biggest impact. Just do it. Keep it simple.
It’s like designing a workout for someone who never worked out regularly. For cripes sake, we have trainers giving people friggin’ wrist curls to do-- WRIST CURLS! Know what I say? WALK! Take a goddam walk! Athletes do wrist curls to fine tune to the 99th percentile.
It’s a nice analogy — REALLY! Take the first, simple, effective step: EAT FEWER GODDAM CALORIES. If you jam the same number down your throat, but they are chock full of health, you are a wee bit healthier (MAYBE), but you’re still not getting around to losing 100 lbs.
Blah blah blah… “Ooh, you should eat more vitamin W, and don’t eat after 5pm, because that worked for me, and then cut back on sugar, and Atkins this and…”
Ah… frig it all. No… go on an athlete’s diet… right friggin’ now! YEAH! That’ll work… even though most humans are incapable of going from completely unhealthy to athlete status. Yes, get on that bandwagon of ‘success’. .
This is like saying “What will make my car go faster? Putting wheels on it or taking out the stereo and saving a pound in weight?”
Put wheels on it first. If you get to the point where that extra miniscule edge matters when you’re in your high-performance bleeding-edge photo-finish race, then take out the stereo.