Yeh, I think Cortisol, Stress, Inflammation, and all that entails these things have a lot to answer for.
Again, my knowledge in this is in it's infancy at best just now.
The first girl I mentioned is actually a more extreme example. Great candidate for exercise addiction, history of anorexia, also very obsessed with eating clean foods (she's a dentist - she HATES sugar). The trainers before her were convinced it was a thyroid problem because nothing would work (and, c'mon, she trained 16 hours per week!!). She eventually got them tested and all was good.
Coincidentally i've since came across thishttp://chriskresser.com/5-ways-that-str ... d-symptoms
I have another women i've trained for almost 2 years who is another good example of this, and has a history of depression.
Also have a male right now who's a good example, one of those stress bombs with a lean body but large gut.
My sister, who I started a thread about on here, became a great example, too. Her weight loss stalled completely, I sent her to a gym in glasgow, they made her lift "heavier" things and take a few protein shakes a day. No other change. She dropped 8lbs in 4 weeks. I have a handful of example of doing this, actually ran 3 clients together the 4 weeks before xmas with a "less volume, more food" approach, and it worked (the older women I mentioned was one of them - she dropped 7lbs in 4 weeks, I added a mid morning meal, mid afternoon meal, and cut her training volume in half).
It's a specific kind of client, though. Almost always people that have lost a lot of weight already, and kept it off. Also will generally have quite highly stressful lifestyles and/or a history of some "stress" related condition. For people new to weight loss and exercise, asking them to do less and eat more will almost always give them the opposite of what they want lol.
Don't ask me the exact mechanism behind it, because I don't know. I'm trying my best to understand it more. I just know that things get much easier to "trial and error" when you forget about calories in vs calories out. I don't pretend to clients that I know everything, I'm 100% honest with them, especially about nutrition, and assure them that i'll work with them find what works for them. The 2 examples I mentioned up until now approached me because they had ran out of ideas and after seeing other Trainers. I was the only one who asked them to do less and eat more. It's worth mentioning i've only had results with one of them so far, but the other has only just started, really.
How can you ask someone who eats so little to eat even less? Or ask someone who does so much to do even more? If you forget calories in vs out, then this is common sense. How can you ask someone who eats so little and does so much, to eat even less and do even more? All I did was ignore calorie calculators on websites and followed my gut, excuse the pun.