HOW THE KETO DIET CHANGES EVERYTHING

Leading biohackers, US Special Forces, NASA, and the most accomplished exercise physiologist on the planet all agree on one thing: That a strict low-carb, high-fat "ketogenic diet" won't just help you lose weight, exercise more efficiently, feel better, and generally improve your life (and even your chances of getting to Mars!) - it may also fight cancer and wipe out diabetes forever. The only wrinkle? It's not for the faint of heart.

- TYLER GRAHAM

Timothy Noakes, MD, is an emeritus professor in the Division of Exercise Science and Sports Medicine at the University of Cape Town.

He's one of the most accomplished exercise physiologists on the planet. You can't walk by a restaurant in Cape Town that doesn't offer a “Noakes option” — say, an avocado stuffed with breakfast sausage and eggs, or a double cheeseburger with lettuce sans bun — and evidence of his teachings seems to be everywhere, mostly in the form of our nation's best-known athletes, including ageless golfing legend Gary Player and eight-time Ironman World Champion Paula Newby-Fraser. In fact, Noakes is a celebrity these days, he’s even been pulled into South African presidential politics: To echo the country's papers of record, “Is President Jacob Zuma’s and his wife's dramatic weight loss a result of the Noakes Diet?” No one is sure about the president, but his wife, definitely: She’s lost 30 kilograms following the Noakes plan.

To high-performing athletes, Noakes preaches that the bedrock tenet of endurance athletic nutrition — that winning performance is best fueled by eating lots of carbohydrates — is simply wrong. Instead, he believes athletes can alter their bodies so that their metabolism burns fat as a primary fuel source, a physiological process known as ketosis, either from stored body fat or from the foods they eat every day.