Diets and research

Most people that wants to be "fit" have gone through a diet.
They've tried different methods to stay fit and healthy and especially slim.
But to what extent should we do this?
I am not against different kinds of diets but I think that if you try to eat healthily that is better than any diet. I don't know if there is a diet that is "the best", what works for someone might not work for me.
There are researchers looking into this all the time. Just recently they have finished a big research about how diets are affecting us.
"More than two-thirds pile the pounds straight back on, raising the danger of heart attack, stroke and diabetes".
That doesn't sound too good now does it?
I think that there will always be researches about different kinds of diets and how they are affecting us, we have to take into consideration what they say and make up our mind what we want to do.