Hello, been lurking for ages, very entertaining and interesting thread. Hope you don't mind me butting in, but I hopefully have something useful to say about the calories/BMR/TDE stuff.
The numbers can be baffling but i think what helps is that it is an indication of what your body actually needs and some people find it useful as a way of getting back in tune with that. Various comments upthread about eating 'empty' calories, scarfing leftovers, grazing without thinking and so on. And also about total change in attitude to food in a sustainable way rather than starvation.
Knowing when you feel full, what makes you feel full, what gives you energy without crashing (i.e. slow release stuff, complex carbs rather than Haribo) and so on is all part of it.
One of the challenges is to recognise and respond to feeling full. I really struggled with this during and after 15 years of bulimia. I also struggled with recognising trigger foods i.e. things that would tip me into a binge and out of control. The nutritional info on MFP is great for this and also the food diary aspect - if you log absolutely everything, you can see the patterns of your eating behaviours and spot the triggers. e.g.:
Sensible eating all day, then a glass of wine (small, sensible, within calorie allowance etc etc) and bang, craving salty snacks, then another drink and so on
e.g. sensible eating all day, get home starving after long commute, can't resist a piece of toast, which becomes 5, then you think, what the hell, I'll have chinese takeaway for dinner.
And so on
Anyway, apologies for the very long post, I hope some of it makes sense.
Use the stats and tools to understand your nutritional needs and the lifestyle change will follow