The most important thing about a “diet” meaning someway of restricting calories, is compliance. No one can stick on any diet that is currently popular; not The Zone, The Atkins, the Ornish, nor the Glycemic Index diet. When the drop outs are considered in the data, the lack of compliance is close to 100%. When you factor in the fatter body composition and reduced metabolic rate caused by dieting and the subsequent regain, the failure rate is over 100%.
Most humans today eat a diet that is far from the original human diet of the past 40,000 years. Those of us on the EF diet do not eat a low-carb diet, everyone else around us eats a very high carb diet of extremely low value nourishment.