Everyone is different and has different goals. As explained in the book The Fast Diet a little like the author Michael Mosley I am a tofi thin on the outside and fat on the inside. Though I did have excess fat, my fat started to add in new areas from my male belly area to my back and pectorals - yuk.
And the key for me is that I have never really dieted at all before. I am keen on keeping fit but my world at the moment doesn't afford me the time to do enough and slowly (so as I didn't notice) and to allow me to eat and drink as I like to be happy. So I knew at some point I needed to do something.
I didnt like the idea of a diet mostly due to their ever too common unsustainable nature and how people YOYO on them. What's the point in going up and down - I suppose you might argue that while you are going back to where you were at least you are not worse..still not an ideal situation for all the sacrifice and hard work.
So at random my partner mentioned this new book and 'diet' not for me to diet as just in passing really and she thinks that I don't need to loose wight (though as I say I know I'm not healthy on the inside as much as I might be). If someone is well based to review diets she is, having tried almost all of them.