If you have ever beaten yourself up as to the reason why you CANNOT lose weight, then watch Tom Naughton's presentation. It's superb, and gives an easily understood rebuttal of '...it's just a problem of you being a glutton and a sloth!' I guarantee it will give you a fresh insight, and more than that; fresh hope!
dietdoctor.com/guess-worlds...
If you want to know the answer to the question at the end, just go through the website, and if you would like to know how to ramp UP metabolism rather than slowing it down (whilst still losing weight), research intermittent fasting with Jason Fung's excellent blog and youTube series.
By the way if you would like an example of complete and utter illogicality (by questioning the diet of the (then) world's oldest woman) click on the link - but to save you the trouble...