Absolutely true for me -- this is mostly copy-pasted from a reply in the Featherweights forum, but I *only* lost weight because I switched to a mostly-vegan (which for me meant whole, healthy foods) diet.
Before: I had always been a carnivore with a lot of fat on me even at a "normal" BMI (and all on my tummy... ugh). As a result, I had ridiculously high cholesterol, was bordering on PCOS, at risk for diabetes, etc... all this at age 20. I decided to go as close to vegan as possible toward the end of August this year.
Why it worked: I stopped weighing myself. But I told EVERYONE that I was trying to avoid all animal products -- and that kept me accountable. I read the literature. I talked about vegetarianism with my friends. I found ethical justifications (empathy, sustainability, economic) and used them to remind me to make the right choice every time.
The shock to my diet -- and it was a huge shock -- also forced me to discover foods and preparation methods I never would have found otherwise: vinaigrettes I mixed myself with apple vinegar and olive oil; hummus; fresh fruit; grilled tofu... the list goes on. I started eating salads regularly. I
stopped eating dessert entirely and this time I knew that I was making that choice out of an external desire -- being ethical -- so it was easier to control myself and easier to prevent "falling off the wagon" if I made any mistake.
What I learned: I'm not a vegan anymore -- I'm happily settled on being vegetarian with low egg and dairy intake -- but I would say trying to cut out animal products entirely was the best health decision I could have made. Mainstream American diets are so reliant on making meat, bread, and butter the centerpieces of the meal that it becomes critical to "untrain" from them.
Anyway, think about it and you realize that most successful diets end up being something like pescatarian or most-vegan-with-a-little-meat -- all that means is that you cut down on the bad, fatty, high-calorie foods and substitute whole foods, veggies, and fiber. Never a bad idea.
The critical reason I chose an "ethical" way of defining my decision was that it kept my body image and self-loathing issues getting in the way of my plan. It kept my late-night snacking (which tends to be on non-vegan carbs... brownies!) innocent -- apples -- and most importantly meant that every PETA-hater I told was another person I would never, never let myself touch dairy in front of

. Oh, and I got to avoid the scale for months and watch the inches fall off.
So that's why I'm staying vegetarian -- I feel better, stay on plan almost without fail, and when I do fail it's easier to get back up. I used to overeat and have a horrible diet, and now I find it much, much easier to control those unhealthy cravings.
