My personal results have been quite successful. I was randomly assigned to the low-carb diet. I basically eat vegetables, meats, and cheese. I avoid everything from bread, to rice, to even nuts and fruits. On this diet I have lost nearly fifty pounds since I started. So it's been pretty successful for me. (I will admit that I had no idea whether it's the particular diet I'm on, per se, or the fact that I'm on any diet at all -- that I am paying attention).
I also accept the premise of the study: one diet does not fit everyone. Sometimes I meet people and they say it's as simple as calories in, calories out. Some people say everyone should be on this diet or that diet. I don't know -- I don't presume that my diet would simply work for everyone. The human body is a very complex system both for any one person, and for the population. I tend to believe the central premise of the study (and we'll see if it works out): that different physiologies lead to different beneficial diets (and perhaps much more).
There is a lot of story here: exercise being easier, meetings going more smoothly, my colleagues and family and friends supporting me, YC giving me a new t-shirt, buying a new wardrobe, my changing interactions with women (I'm strait, and who knows if this is due to me looking better or me being more confident)...etc...I'm planning to write up a (as is often the case) too-long blog post on it all when I'm finished with the study on October.