At first, it was to lose the couple of pounds I had put on over the holidays and just couldn't get off, regardless of the fact that I was working out probably 6 days a week (and not wimpy workouts either!). I was looking into CrossFit and came across the Whole30 website, which is basically just a ramped up version of the Paleo diet. Supposedly, by cutting out all grains, legumes (including soy and peanuts), dairy, sugar, and alcohol, I would "change my life in 30 days". This left meat, chicken, seafood, vegetables, healthy fats, fruits and nuts. There's a whole bunch of science behind it, but I'll let you research that. What spoke to me was that it was all about getting back to real, unprocessed food. I thought I'd give it a go.
Here are some links to some of that research I'll let you go do. :-)
The Paleo Diet
The Primal Blueprint