This question has frequently been debated by food critics, scientists, health and fitness fanatics, nutritionists and health care professionals over the past few decades. I personally feel, through my own experience with the diet and seeing the results some of my clients make, that the Palaeolithic Diet is the way forward (or Paleo Diet for short).
In fact, this was the most googled diet in 2013 and 2014.
It is the healthiest way we can eat and takes us back to our caveman ancestry thousands of years ago. In a nutshell, it consists of anything you can hunt, fish or gather from a tree or a bush. Meat, fish, vegetable, fruit, nuts, seeds etc. Basically, what humans were designed to eat. None of this processed rubbish.
One client of mine lost 4kg in a week, simply through changing over to this diet!
Alongside weight loss and fat reduction, it has a number of health benefits as detailed in this diagram below, taken from the following website, which gives a more in depth overview of this way of eating.