After 12 days eating what producers dubbed the "Evo Diet", the group's cholesterol dropped 23%, their blood pressure dropped from 140/83 to 122/76, and though it wasn't intended to be a weight loss diet (~2300 calories/day) their weight dropped an average of 9.7 lbs.
There are some fair criticisms of this diet in the comments section on BBC's article. I agree with Matthew London's take... It wasn't a scientific study so they didn't account for confounding factors that may have contributed to the outcome, namely what effect living in a relaxed, non-work, non-hustle-bustle environment where all your needs are provided by outsiders would have on your BP, stress hormones, lipids, etc.
Still, I cut it some slack since it was designed primarily to titillate TV-watchers. All-in-all, I think eating more fruits and vegetables and fewer processed foods is a great goal. I only wish our ancestors had evolved to drink coffee.
One thing that's odd. The fruit- and vegetable-based "Evo Diet" stands in contrast to the meat-based "Paleo Diet". Just what did humans evolve to eat?