we were just talking about this the other day. There is a guy that I know that lost a ton of weight by switching over to a vegetarian diet and then another that did the Atkins thing. The one that i think is really complicated if not impossible where I live (i'll be honest and say that I didn't investigate it much) is Keto... that seems like so much discipline would be involved that i probably would give up pretty quick.
I think the one thing that does work relatively universally is to simply eat more whole foods and don't consume too much of anything that is kind of well known for being bad like pasta.
oh, and of course exercise a bit :)
Keto is indeed tough, and involves a lot of prep and work on the part of the person who is doing it. I admit I don't know a great deal about it, but those devoted enough to stick it out swear by it so there must be something to it.