Are carbs the new fat? For much of the second half of the 20th century, doctors constantly suggested we avoid high-fat foods, but more recently a new target for our dietary scorn has emerged: carbohydrates. Two new companion studies are suggesting a ketogenic diet – high fat, low protein, and low carbohydrates – could enhance memory, improve physical strength and extend lifespan.

Whether you want to call it the Atkin's Diet, Paleo or simply "Keto," there have been plenty of variations on this way of eating. While some diets suggest no carbohydrates or sugars, many are underwritten by the same theory. The idea is that by severely restricting the body's intake of carbohydrates, a state known as ketosis is entered into. This forces the body to burn stored fats as fuel instead of carbohydrates.