I found this article about a doctor and how she lost weight.
Interesting articles, especially the one about 10 reasons your body thinks you're hungry. If my MD was obese yet telling me that I needed to lose weight it would be hard to take him/her seriously somehow.
I can't comment on diet plans from personal experience, although I know several people who have had success with Weight Watchers. I do the old "eat less and move more" strategy when I have the willpower or motivation to lose some weight. Sometimes I'll set a calorie limit and count the calories of what I eat (time consuming because of the weighing, measuring, etc) but more often I just work on making good food choices, limiting portions, and limiting snacks and sweets (sweets are my downfall) and increasing activity. When I stick to that consistently I do lose weight.
I have worked with a trainer once, for 6 months, and had great results. It was pretty expensive so I was very motivated to get the most out of it possible.
A bit of both.
How does that plan work?