Jeff Browning, also known as Bronco Billy, is an icon in the ultra-running world. He is a proven and versatile mountain athlete even in the face of extreme temperatures. With 5 finishes under his belt and placing in the top 10 in all but one of them, he’s more than familiar with the Western States course - and the heat. Jeff Browning will be competing for the 6th time this year at Western States. He is also the latest champion of Hardrock 100, when the race last ran in 2018 and will be racing it just a few weeks after Western States this year on July 11th.
The Evolution of a Diet: From Vegetarian to Fat-Adapted
For about seven years in his 20s, Browning was a vegetarian. “I didn’t think I did very well on that diet, and my wife definitely did not,” he says. “I lost a bunch of muscle mass, even while lifting weights. I couldn’t handle getting soft and it told me that something was not quite right.” In 2004, the Brownings shifted to a whole foods diet - clean meats, grass-fed meat, organic fruits and vegetables, whole grains - for about 12 years. Then when he hit his 40s, Browning noticed another trend - he started having trouble getting down to race weight and his energy was sapped. “I found that things weren’t just clicking.”
After a race in South America, where he drank some questionable water, Browning experienced health issues, including candida - a yeast overgrowth that can cause an infection. He endured seven uncomfortable candida flareups in 2015. Browning continued to race amid the struggle. After a long week of research, he concluded the paleo diet would be the solution and dug into the research on the candida diet, keying on the fact that yeast is fed by sugar.
“We cut out grains. We cut out sugar. We were already pretty low sugar, but were eating spelt pasta and rice. We just cut all of that stuff out,” he explains. “We - the whole family - just went cold turkey. It was rough at first, but within a few days, my candida cleared up and went into remission.”
Embracing Fat Adaptation: The OFM Approach
After multiple flare-ups of candida in 2015, Jeff started to dig into the idea of cutting out sugar and grains in his everyday diet. Yeast feeds on sugar, so it made sense to quit feeding the yeast. This research led him to information about using daily diet to make a metabolic shift toward “fat adaptation,” also known as “optimized fat metabolism (OFM).”
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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 Jeff discovered through this personal exploration of healing his 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. He just needed to give his 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.
Navigating the Modern Grocery Store
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, Jeff 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. He kept his protein moderate, while restricting carbs during the first four weeks to encourage the metabolic pathway to open up and burn on-board fat.
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After that first month of eating ketogenic to encourage the fat-burning pathway to open, Jeff then increased his intake of carbs by sticking to a list of foods from Bulletproof, Primal Blueprint, and Paleo sources. He 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 his baseline carb, he strategically added fruits and tubers - sweet potatoes, red potatoes, gold potatoes - back into his diet on workout days. With his on-board fat pathway open, adding naturally low-glycemic carbs brought all the pop back. His recovery and low-inflammatory response was amazing. He found he could run easily for up to 3 hours with zero calories and no dip in energy. On efforts over 3 hours, he kept using simple carbs like diluted carb drinks and gels, albeit less per hour than previously. He 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 his long runs suddenly became rocket fuel. What he found was the metabolic flexibility of two fuel sources - carbs and fat-supplying his endurance energy needs.
Dispelling Myths and Misconceptions about Fat
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, Jeff has had a lot of “low-fat” propaganda beat into his head. As he started to uncover some of this information, he 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. He 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 Benefits of LCHF: Jeff's Personal Experience
Lighter and stronger since that change 2 ½ years ago, he has had a couple of minor flareups - usually after a 100-mile race when is immune system is compromised and consumed additional carbs that week. A candida diet is defined as one that is low-sugar, anti-inflammatory and promotes good gut health while eliminating the sugars that feed a candida overgrowth. The diet includes non-starchy vegetables, some low sugar fruits, non-glutinous grains, fermented foods and healthy proteins.
Browning focuses on clean meat, most vegetables, some fruits but has cut out potatoes. Notably, he has lost eight pounds and two inches off his waist, getting back to his high school weight. “My weight-to-strength ratio went up because of the diet. I feel great. My energy fluctuations during the day stopped.” The sugar cravings stopped. “I always thought I had a sweet tooth, but after this, I don’t crave sugar anymore,” he says. “For me personally, it was a new level of clean. I felt good. I recovered quickly. I stopped having the inflammation that I was having after races.” After 100-milers before the diet, Browning would have to wear compression gear, had swollen ankles and knees, and experienced issues getting down stairs the days after the race. But since adapting the diet, “All of that went away,” he says, noting he reached out to Zach Bitter for advice on the diet. “Recovery was off the hook. That’s one thing that Zach had told me that recovery would blow my mind.”
Just a couple of months after the diet change, Browning finished the Hurt 100 around 3:30 on a Sunday morning. Later that afternoon and the following day, he was doing air squats “and my quads were just a little sore. I couldn’t get over the difference in recovery.”
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Protein Intake and Quality
When it comes to protein, he says it’s about the same as before “but after hard efforts, I up the protein. As an endurance athlete, you have a definite need for protein. You are cannibalizing muscle, breaking down muscle. You can go up in protein intake as compared to someone who runs 20 or 30 minutes a day.” But, he emphasized, the quality of the protein is even more important. He encouraged the consumption of wild and grass-fed meat instead of corn- and wheat-fed meat. “Not all meat is created equal,” he says. “You have to know how it is raised and how it should be raised. Let’s quit trying to throw grain down everyone’s throats, making people sick and creating an obesity and heart disease epidemic.”
Long Run and Race Day Nutrition Strategies
Number one, you are topped off for the first hour, so you just need to sip a little liquid to thirst. That could be some light carb calories in one bottle or water, but you do not have to be actively consuming calories the first hour. Something with light electrolytes or something like that. Now I like to think about an IV drip of calories coming in during a long run or a race. Another strategy is to just carry water and have a small flask, five or six ounces, that you could put concentrated calories into like a gel. Add a little water to it so it’s a little more liquid-y and that makes it go down easier, plus it’s easier during colder weather and not as hard to get out. Then you can just take little hits off it every ten minutes or so. Now I do think that gels can be used strategically around heart rate rising runs because you are going to burn more glucose, so if you pop a gel before a 2000 foot climb, that’s a good strategy because your heart rate is going to creep up on that climb and it’s going to give you a little extra. You’re going to burn a little higher carb ratio from fat and then it’s going to give you a boost on that climb but your baseline should be some kind of light carb calories coming in, whether that’s a concentrated gel in a flask or something like that so you don’t have to take a whole gel you can just take sip little sips of it constantly. Now, the other thing I like to think about besides calories, and I would say start with 200 to 260 calories an hour and see how that works. Most people are going to be somewhere in that range of those 250 calories an hour. You can train yourself to do 300, that’s tough, but I find that if you’re IV dripping calories, you will not have lows if you’re constantly kind of dripping, sipping. You also want to think about liquid intake. Depending on the heat, sweat rate, and conditions, sometimes it’s going to be a hot race, sometimes it’s not going to be so hot. You are going to be somewhere in that half a liter to a liter an hour, ballpark, so that’s a good zone to be in because you know you’re not going too low but you’re not drinking too much, and everyone is going to be different. Some people are going to be lighter sweaters and less salty sweaters and some people are going to be heavy sweaters and salty sweaters like myself, so my drink rate is a little on the higher end of that range. In a really hot race, it might be 1.3 liters an hour but that’s kind of my max. Forty ounces an hour is about the most I will drink and that will be my drink rate. Now that kind of covers calories and you can eat a little bit extra solid food, but I like to go for calorie dense foods like fruit at the aid stations or a little broth, something like that. Keep it simple, something that breaks down very simply. Now if do eat complex foods during a race or a long run, eat them more sporadically. Let us say every two to five hours. Most people are going to be somewhere around three to four hours apart. The third thing is sodium intake. Now sodium and potassium are what you lose in your sweat. These need replenishing. You want to look at all your calories, what you are consuming and how much sodium you are getting. You want a little potassium in there, too. That is about your drink rate, so you need to make sure that anything you’re consuming if it’s calories with electrolytes in it, make sure that you’re hitting that range of sodium intake because the sodium’s responsibility is to mineralize the water you’re drinking so it gets across the gut wall into the bloodstream and absorbs faster. That’s one of the problems of sloshy gut. That means that you probably do not have enough sodium per liter which means it is just not absorbing. Now there are outliers. I’ve had a few athletes over the years that just needed a little bit of sodium, more like 400-500 milligrams, but their drink rate was lower too, so it usually corresponds to drink rate. If you are going to supplement any kind of electrolyte pills or anything like that, use it to get you to that range per liter. So go use that in your training.
During the 2018 Western States, Jeff noted: "It’s difficult to consume as many calories in the heat, so I take in a lot more liquid calories. Usually I shoot for 1 liter/per hour to drink and ramp up to around 1.3 liters per hour when it’s hot. I get some through sports drinks - 1 bottle of electrolyte mix and 1 bottle of water."
He also emphasizes the importance of looking at the label of salt capsules, noting that a lot of electrolyte caps have too much calcium and magnesium. Dehydration is really hard on your kidneys and you’ll know you’re in the danger zone when you can’t pee. While he has experienced minor cramping during a race, he credits his upbringing in the heat and humidity of Missouri, where he spent summers baling hay and playing football, for his ability to handle extreme temperatures.
LCHF and Endurance Performance: Scientific Insights
Despite the high-carbohydrate tradition in running, some endurance athletes are going against the grain and choosing low-carbohydrate, high-fat (LCHF) diets in an attempt to change the way their bodies use energy-using fat stores first and reserving glycogen stores for later. LCHF is a general term, while the name Ketogenic is reserved for a diet high in fat, moderate in protein and very low in carbohydrates (less than 50 grams per day on average). While exercising at lower intensities (because the activity is sustained, ultrarunners are typically in the middle range of VO2max), fat is utilized more readily by the body and actually produces more energy per gram than carbohydrates. In a 2016 Metabolism journal study, endurance athletes followed a LCHF diet for an average of 20 months and reached a maximum fat oxidation rate of 1.5 grams/min at 70-percent VO2max, 50 percent higher than what carbohydrate-adapted endurance athletes have ever reported. The LCHF group also maintained their ability to replace stored carbohydrates-a feared downside of the diet. In addition to regulating energy, reducing carbohydrates during races may lead to less gastrointestinal (GI) distress because the body can only process a certain amount and type at one time. Additionally, inflammatory markers could be reduced, allowing for faster recovery. Browning has been on a LCHF diet for nearly four years and prescribes it to many of his athletes as well. He admits that initially, the switch can be tough, as there are variations in how long it takes to adapt. In the end, the gains have been worth it for him. “I have experienced less GI distress during races,” he says.
Considerations and Caveats
Browning adds, “There seems to be a lot of confusion around this style of eating because many people think you must eat ketogenic all the time and that you don’t use carbohydrates during races. But that’s not true. At higher intensities (above 70-percent VO2max), the body relies on aerobic metabolism, which requires use of carbohydrates, meaning a LCHF diet might not be appropriate for athletes focusing on shorter events. Only a few studies address this issue, and many fail to account for changes in body weight and composition, which can affect performance. For example, one 2014 Nutrients journal study reported that maximum power output in well-trained off-road cyclists was significantly decreased after four weeks on a LCHF diet. However, the study reported lower body mass and body fat for the athletes, which was not normalized in the results of the study. Dr. Trevor Bennion, a metabolic research specialist and owner of Fitness and Physiology in Fort Collins, Colorado, is skeptical about using the LCHF diet as a training tool for this reason, saying, “For an endurance event, being able to handle a specific volume [combination of intensity and duration of exercise] relies on being able to utilize carbohydrates effectively. Metabolic changes incurred may not only affect muscular fatigue, but the central nervous system as well, impacting motivation.
Adaptation and Monitoring
Expect to have lower energy for 7-14 days. Keep runs below 2.5-3 hours. Some athletes will have symptoms, including: headaches, nausea, irritability, muscle cramps, lack of focus and sleep issues. Adaptation occurs when symptoms subside. Monitoring ketones via a breath monitor or urine strips offers more precision. Add ¼ tsp. Introduce foods like fruits and sweet potatoes around hard efforts and volume (i.e. hard workouts and long runs). Ongoing eating pattern emphasizing whole foods, limiting grains.
A Typical Day of Eating for Jeff Browning
Okay. Breakfast is typically two eggs, over easy, with organic coffee with MCT oil and heavy whipping cream (unsweetened). Or sometimes I’ll do a raw egg in raw milk and drink it Rocky style. Then I train at noon (no carbs yet). After training, I’ll have some meat and greens at around 2pm, all smothered in olive oil. Then my wife and I will cook up a nice Paleo dinner together-typically meat, veggies and sometimes sweet potato-especially if I'm in a big training block.
Recommendations and Resources
Number one would be Primal Blueprint by Mark Sisson. And for a geeky read, I would recommend The Art and Science of Low-Carbohydrate Living by researchers Volek and Phinney.