You may be aware that I have been on a Low-Carb, High Fat (LCHF) eating plan since last September and although I have not been very public with my results, I feel that this is the best way-of-eating for me. What is LCHF? It is where you get most of your calories from fats and the least from carbs. Typically your total calories are from 75% fats and saturated fats, 15% protein and 10% carbs. On this plan I have maintained my weight at the lower end (about 144 lb.) of the last 15-years range (140 -160) without spending all my time running or riding. In fact, I took the fall and winter off from training, only doing small workouts and some weights. Those of you that ride with me on Tuesday night know that I am not as strong climbing, but my overall average speeds are not bad for not training, and I have good endurance. Since I am now training for the Army 10-mile run race in October, I have been even more interested in how well I can perform on a LCHF diet.
I recently read a book on this subject — “The Art and Science of Low Carbohydrate Performance” by Volek and Phinney, two doctors who have evaluated the performance of LCHF athletes. In this book they discuss that once an athlete becomes keto-adapted, that is where their primary source of energy comes from fat, their endurance levels will increase dramatically. We have about 2 hours of stored carbohydrate that can be used for energy in our bodies, but even the leanest person has more than twice that amount stored in fat. But that fat is not available unless you are keto-adapted.
I came across a blog post from Sami Inkinen, an elite triathlete that sparked my interest. It is an experiment of 1, but quite controlled and he has very interesting results. He has measured the type and amount of energy used during controlled tests using the same equipment 3 time while going from a high carb diet to a LCHF diet. On the first test, he was eating a high-carb diet and guess what…. he has about 2 hours of carbs available and even though he had done hours of training in his “fat burning zone” he could not exceed 200 calories per hour from fat-burning at race efforts. Hence he would run out of energy once his carb stores were gone. A year later he did a second test on a moderate-carb/moderate-fat diet and his fat-burning numbers increased significantly, to 400 calories per hour at the same race effort. Finally, he performed a third test on a LCHF diet with the same parameters and increased his fat burning ability to 600- 750 calories per hour. The chart says it all. At 300W his bonk-time went from 2 hours to 5 hours! Interested? I am. I would love to see what happens with elite athletes such as marathoners and pro-cyclist if they were to go low-carb. I’ll let you know how my “experiment of 1” goes…
Endurance on LCHF diets.
The FitnessEDGE 