I am of the opinion that individuals have different composition and body types. What works for one, many not work so well for others. I also believe that the primary reason diets fail is for a lack of discipline and self control.
Now before you want to flame me, I was 6 foot 260 lbs. I am now down to 190 - 195 and working on taking off the last 15 lbs. I did it by making a series of small changes over time. the first thing I changed was my coffee. Once I had taken off 15 to 20 lbs, I would stabilize myself at that weight for a while and then back at it to take off the next 15 to 20 lbs. Stair-step dieting I call it.