I have tried many diets in the past. I know all the rules, at least for the most part, but I have issues with willpower.
My husband and I both have to lose weight. We've gone to a nutritionist, but again I didn't learn anything new. I just have to DO it. Don't eat empty calories. Don't eat junk food. Choose whole grains over simple carbs. Have more vegetables. Drink more water and don't drink pop (my biggest weakness - but I haven't had any pop for a week). Limit fat, and choose good fats over bad fats. Portion control. Etc. I think my problem is mainly motivation and willpower.
I was naturally thin growing up, and through my 20s, and I just never developed good eating habits because bad eating habits didn't cause me problems - at least not the immediately visible problem of weight. Then my metabolism got slower as I got older, and I had a baby and put on weight there, and with my bad eating habits, I ended up with a lot of extra weight on me!
I have been lurking and there are so many people who post here who have been truly successful, and who have maintained for a long period of time. Seeing that is huge motivation. I'm really hopeful I'll be successful this time. I want to get really old someday and getting to a healthy weight will help in that goal.