From a NYTimes interview with Dr. Jules Hirsch, who has researched obesity for 60 years....
"What would you tell someone who wanted to lose weight?
I would have them eat a lower-calorie diet. They should eat whatever they normally eat, but eat less. You must carefully measure this. Eat as little as you can get away with, and try to exercise more.
There is no magic diet, or even a moderately preferred diet?
No. Some diets are better or worse for medical reasons, but not for weight control. People come up with new diets all the time — like, why not eat pistachios at midnight when the moon is full? We have gone through so many of these diet possibilities. And yet people are always coming up to me with another one.