I don't believe in special diets.. really It's about eating more veggies and fruits than usual and reducing portions overall.
Of the diets the paleo diet aka caveman diet seems doable (lots of veggies and fruit, very little carbs), and the zone is really annoying (weighing your food? really!?)
Any time you change you make an ongoing change to your diet that deviates from your normal eating habits, or from the way you want to eat, I'm pretty sure you're on a diet. And considering the rate of obesity, diabetes, heart disease, etc., in America (and elsewhere), I'd say dieting is kind of an imperative right now.
The Warrior Diet, which has a stupid name, is based on the premise that evolutionarily, we are not meant to eat multiple meals per day. As hunters/gatherers, we used to spend the day hunting and only had a big meal at the end of the day once we were safe from harm. Wild animals behave in generally the same way. But when captured and put in captivity they will eat and eat and eat until they get fat, sick and die. So zookeepers have to ration their food and manage their diets to protect them from themselves. The warrior diet is based on the premise that humans are, in a sense, in captivity. We no longer have to hunt for our food. We're not in danger. We live sedentary lifestyles. And we behave, dietarily speaking, as if we are living in captivity.
I won't say that I buy it lock, stock, and barrel (I simply don't know enough about us), but it is intuitively appealing at least. It's an interesting and plausible idea. Also, I've been doing it, and I feel great. My fat is disappearing quickly, and I go through the entire day with lots of energy and alertness, entirely free of periods of sudden sleepiness.