Weight Loss/Maintenance

Has been proven effective. Actually, any diet which raises fiber and reduces sugar will work. It's mainly the sugar--it will increase your appetite something fierce, as well as raise your cholesterol, blood pressure, and blood sugar (insulin resistance), but any overly processed foods are way too easy to eat to much of will add too many calories.

I like Andrew Weil's approach. He says eat for health as well as weight loss. His food pyramid is very Mediterranean-like. Mostly plant based foods, with some servings of dairy, fish and even meat allowed. And healthy oils in moderation.