Fat. That tiny word has caused quite a stir as of late in the world of endurance sports. And with good reason. An increasing number of athletes are turning toward the previously shunned food group and experiencing big results.
After multiple flare-ups of candida in 2015, I started to dig into the idea of cutting out sugar and grains in my everyday diet. Yeast feeds on sugar, so it made sense to quit feeding the yeast. This research led me to information about using daily diet to make a metabolic shift toward “fat adaptation,” also known as “optimized fat metabolism (OFM).”
The idea is not a new one. It’s actually been around for thousands upon thousands of years. Our hunter-gatherer and hunter-herder ancestors went with the flow, following a cycle of the seasons. History suggests they only ate a higher carb diet when things were ripe and in-season, defaulting the remainder of the year to a lower carb eating pattern. They relied on more fats, organ meats and proteins in the winter, spring and early summer months.
Our bodies are really good at being flexible. Metabolic flexibility has given us a good edge on this planet for thousands of years. And as any endurance athlete understands, with a little stress comes adaptation — whether training for that next trail race or a natural restriction phase through eating seasonally. The latter is a practice that has died over the last few generations. We now have a handy convenience of the commercial grocery store, and the ability to consume most foods at any time of the year, whether they are in-season or not. Those seasonal eating patterns and periodic restrictions that humans used to experience are either non-existent or so few and far between, that we no longer see any seasonal adaptation.
What I discovered through this personal exploration of healing my own system was a dormant metabolic pathway just sitting there waiting to be tapped into — the ability to burn a high rate of on-board fat for energy at a very high aerobic rate. I just needed to give my body that ancient seasonal adaptation phase. The key is keeping insulin stable every day. I did this by shifting my eating patterns to mirror more naturally lower glycemic carbs from paleo/primal sources, while replacing my former high carb intake with healthy monounsaturated and saturated fats.
Our modern-day grocery store can be quite challenging in this department. Most of the food stocked on the shelves of your local store is full of added sugar or processed grains that have a major effect on your blood sugar. This rise in blood sugar makes your pancreas kick out a bunch of insulin, telling the body to store fat, thus making it impossible to tap into and burn on-board fat stores.
To start the initial adaptation phase, I initially followed a ketogenic diet that restricted carb intake to around 50-70 grams per day (mainly non-starchy veggies and a single, small serving of low-glycemic berries), while replacing all those carb calories with fat calories. Remember that metabolic flexibility we have? Well, it turns out we have the ability to turn excess protein consumed to glucose through a process called gluconeogenesis. So, you do have to concentrate on fat consumption, not protein. I kept my protein moderate, while restricting carbs during the first four weeks to encourage the metabolic pathway to open up and burn on-board fat.
After that first month of eating ketogenic to encourage the fat-burning pathway to open, I then increased my intake of carbs by sticking to a list of foods from Bulletproof, Primal Blueprint, and Paleo sources. I also started to play with the strategic timing of carbs around harder efforts (long runs/races, functional strength workouts, speedwork, hill repeats, etc.). With veggies as my baseline carb, I strategically added fruits and tubers — sweet potatoes, red potatoes, gold potatoes — back into my diet on workout days. With my on-board fat pathway open, adding naturally low-glycemic carbs brought all the pop back. My recovery and low-inflammatory response was amazing. I found I could run easily for up to 3 hours with zero calories and no dip in energy. On efforts over 3 hours, I kept using simple carbs like diluted carb drinks and gels, albeit less per hour than previously. I went from previously eating 300-500 calories per hour during a long run or ultra marathon, to consuming less than 200. Strategic carb use on my long runs suddenly became rocket fuel. What I found was the metabolic flexibility of two fuel sources — carbs and fat-supplying my endurance energy needs.
Since a majority of caloric consumption comes from fat, this can be alarming to some folks who are still stuck in the old nutritional paradigm. The majority of the public is unaware of the emerging science on fat’s health benefits and the shoddy science behind the diet-heart hypothesis that demonized saturated fat and cholesterol, and drove our current dietary guidelines. Being a child of the 80’s, I’ve had a lot of “low-fat” propaganda beat into my head. As I started to uncover some of this information, I devoured podcasts and lectures by Dr. Jeff Volek and Dr. Stephen Phinney, two of the leading and most published researchers on the subject of a Low Carb, High Fat (LCHF) diet. I uncovered a lot of interesting information on how our dietary guidelines, nutritional curricula and food has been influenced by the grain and sugar industries. Bottom line — if we’re getting a majority of our carbohydrates from fresh, unprocessed sources like vegetables, fruits and starches, we shouldn’t be afraid of fat. The emerging science over the past two decades suggests it’s the best for weight maintenance, steady energy and healthy bio-markers.
About the Author
Jeff Browning (aka Bronco Billy) is an endurance coach and professional ultra runner. He has finished well over 100 ultras on four continents, and has eaten more than his share of coconut oil and grass fed butter. Find out more about his running and coaching, and be sure to join his Trail Tribe video tips at GoBroncoBilly.com.
Additional Reading on Fat and Diet
The Art and Science of Low Carb Performance
By Jeff Volek PhD, RD and Stephen Phinney, MD, PhD
By Mark Sisson
By Dave Asprey
The Big Fat Surprise
By Nina Teicholz
Exploring Eating Habits to Achieve Fat Adaptation