Paleo Diet. Don't know why it's called a diet. You can eat as much as you want, and the pounds drop off.
Basically it's eating the way our ancestors ate before industrialization -- eat grass-fed and finished meat (you would be surprised what today's commercialized animals are fed which is passed on to us), pastured chickens (don't be fooled by free-roaming), eggs from pastured chickens, wild caught fish, fresh seasonal vegetables and fruit, preferably organic. Don't eat GM (genetically modified) foods such as soy and corn. No grains, sugar, or processed food.
This lifestyle is healthy! Especially anyone suffering from modern-day health problems (allergies, high blood pressure, high cholesterol, heart disease, diabetes, etc.,) will notice a difference.