I'm always hearing about the latest diet fad, it seems. I'm not a big fan of changing my diet in a way that I don't feel like I can keep up for my whole life - because I've tried and failed on enough "quick fix" diets to know they don't work for me for any sustained period. I also tend to rebel when I forbid any particular foods to myself, so there's no forbidden list for me. While I would love to see a huge weight drop and suddenly find myself fitting in my old "thin" clothes, I don't think that's going to happen for me in a big hurry.
What has worked for me is very slow and steady weight loss since I began running again in 2000 - ten pounds a year or thereabouts for four years (with time off for having babies, which had me flat on my back in a hospital for a solid month less than two years ago). This slow and steady 40+ pound weight loss sure beats the alternative, which would have been an equivalent weight gain, I'm positive of that!
The permanent habit change I am trying to instill right now is eating more vegetables. What I have been doing every night at dinner is eating a HUGE salad (and I mean HUGE - serving bowl size) as my first course, with lots of low-calorie stuff chopped up in it and olive oil and balsamic vinegar dressing on top. That tends to fill me up and I'm not hungry for much else for dinner. It also takes quite a while to eat and leaves me feeling like I've eaten something of substance, and helps me avoid less desirable food choices and grazing during the evening.
I'm still working on incorporating more calorie-burning exercise on a daily basis - I tend to do harder workouts three days per week or thereabouts, and I think it would do my metabolism more good to have instead daily fat-burning workouts early in the day. That's still a change in progress.
Discipline and consistency are keys, or so I hear. Those are attributes that I admire, but never have seemed to incorporate in my eating or workout habits. Never say never, though. I'm starting to make changes I used to think were not sustainable.