Carb-loading is so synonymous with endurance sports it may come as a shock to learn it's not optimal for performance.
Sports science expert Dr. Tim Noakes said endurance athletes can perform as well as — or better than — those following a high-carb diet.
Low-Carb Diets Enhance Weight Loss and Fat Oxidation
According to Noakes, a physician and professor at the University of Cape Town in South Africa, athletes who become adapted to a low-carb diet can use fat as fuel instead of relying on huge amounts of pro-inflammatory carbohydrates.
“Studies of elite athletes chronically adapted to low-carbohydrate diets have uncovered one unexpected finding — their extraordinary ability to produce energy at very high rates purely from the oxidation of fat,” Noakes wrote in the British Journal of Sports Medicine.
Noakes and his colleagues, Drs. Jeff Volek and Stephen Phinney, said the field of low-carb sports performance is underinvestigated and in need of further exploration. Meanwhile, in 9 of 11 low-carb performance studies, a low-carb diet was better than, or just as effective as, a high-carb diet for endurance performance.
Drs. Volek and Phinney are the co-authors of The Art and Science of Low Carbohydrate Living, widely considered a seminal LCHF diet book.
Ironman Triathlete Followed a Ketogenic Diet
Drs. Noakes, Volek and Phinney aren't the only proponents of low-carb diets for endurance athletes. Fitness expert Ben Greenfield trained for the 2013 Ironman Triathlon World Championships by following the LCHF ketogenic diet, and completed the epic endurance race in an impressive 9:59:26.
The Ironman triathlon consists of a 2.4-mile swim followed by a 112-mile bike ride and then a 26.2-mile marathon, done in that order without a break. Greenfield's breakfast the morning of the Ironman was a half-stick of butter, two shots of MCT oil, and a cup of coffee — a stark contrast to the vats of pasta most endurance athletes inhale before a race.
Ben discussed his ketogenic diet experiment on a podcast with fitness trainer Sam Feltham (see video). Feltham himself made headlines after experimenting with a 5,000-calorie-a-day diet that underscored the weight-loss benefits of eating more fat.
When Sam followed a low-fat, high-carb diet for three weeks, he gained 16 pounds and almost 4 inches in his belly. Surprisingly, when Feltham ate a low-carb, high-fat (LCHF) diet for three weeks, he gained only 2 pounds but lost 1 inch from his midsection.
Greenfield joins a growing number of endurance athletes who are sold on the health benefits of a high-fat diet for endurance training. Ben previously followed a high-carb diet but switched after realizing that too many carbs fuel inflammation, which can lead to heart disease, Alzheimer's, obesity, diabetes, and cancer.
"Two years ago, I came across research about pancreatic fatigue and failure, loss of insulin-cell receptor sensitivity, and surges in blood glucose leading to inflammation," said Greenfield, author of Beyond Training. Greenfield no longer follows the ketogenic diet, but advocates consuming plenty of healthy fats.
Weight-Loss Expert: Eat Fat and Get Thin
Meanwhile, recent scientific research and reports suggest that unprocessed saturated fat is good for you and can protect against heart disease, obesity, and diabetes.
Weight loss expert Dr. Eric Westman, director of the Duke University Obesity Clinic, has helped hundreds of morbidly obese people lose thousands of pounds on the LCHF ketogenic and Atkins diets. He said eating more unprocessed fat can enhance weight loss and improve health across the board.
"I tell my patients not to fear the fat," said Dr. Westman, author of New Atkins for a New You. "Eat lots of fat. Fat makes you feel full. There's no problem with fat. In fact, saturated fat — the fat that we've been taught not to eat — raises your good cholesterol best of all the foods you can eat."