Diet = Die with a T at the end of it.
Research Paleo. Research Vegetarian. Research Vegan.
Each week, substitute one unhealthy/processed food item with something from the above three categories. Keep substituting throughout the week till you find a food you enjoy. Then do the same thing the next week, then the next, etc. etc. etc.
That way when you finally reach the look you're going for, you'll already have a solid and sustainable "diet" that you put together yourself, and is likely way more healthy than a cookie cutter diet plan from some for-profit book.