I recommend this excellent summary of the Paleo diet written by George Dvorsky of iO9. Referring to the rising rates of obesity, diabetes and other modern diseases, Dvorsky declares an increasingly apparent observation: "When it comes to our eating habits, it's clear that we're doing it wrong."
Part of the problem is that virtually everything we thought we knew about eating is wrong; the current health crisis is in no small part caused by widespread and pervasive food confusion - and much of driven and reinforced by the modern food industry. As counterintuitive as it might seem, we now know that saturated fats are good and that salt has been unfairly vilified. It's becoming apparent that whole grains are extremely unhealthy, and that sugar is far, far worse than we previously thought, a conclusion that has led some experts to essentially describe it as poison.
Consequently, a new approach to eating has emerged called the Paleolithic Diet, or simply "Paleo" for short. Advocates of this diet focus on eating unprocessed foods like lean meat, seafood, roots, tubers, fruits, and vegetables. Not only are these foods comprehensible to the human digestive system, they pack much more nutrition per calorie than typical Neolithic and processed foods.
The increasing interest in Paleo nutrition is evidenced by the growing number forums including the Ancestral Health Symposiums where:
.... a niche group of scientists, medical practitioners, and health experts are paving the way for what is likely to become a health and wellness paradigm for the future.