What did Dr. Ian Lake want to prove by running 100 miles in five days while fasting the entire time?
“If I can run 100 miles without eating, it means that you can skip breakfast safely.”
Years after successfully adopting a ketogenic diet to manage his Type 1 diabetes, Dr. Ian Lake found himself dismayed at how dismissive the medical establishment still was about the treatment that he says had changed his life overnight. Diabetes experts are still mostly advising their patients to eat a certain number of carbs in every meal, and are still cautioning against low-carb diets and intermittent fasting, often telling scary stories about the hypoglycemia or ketoacidosis that would result.
So, he decided to do something extreme. Dr. Lake decided to prove, himself, how well the body thrives without carbs. And for good measure, he didn’t just skip carbs. He skipped food entirely.
“I wanted to reassure people that the ketogenic diet was a safe practice. And I thought the best way to get the point across was to be as outrageous and audacious as possible.”
With the ZeroFive100 Project, Dr. Lake put together a diverse team of eight to run 100 miles over the course of five days, all without eating a thing. That’s five days, zero calories, and 100 miles. It sounds insane if not impossible, but the team—two with diabetes, and six without—completed its goal last month.
“We all felt euphoria. There were no arguments, no disagreements. We felt more energized as we went on.”
Dr. Lake’s story starts when he was diagnosed with Type 1 diabetes about 25 years ago. During the first two decades of life with diabetes, he enjoyed moderately successful glycemic control, with HbA1c’s generally around the 7.5-8.0% range. “It wasn’t anything to be proud of, but I was getting away with it.” Getting away with it, that is, until he wasn’t. The early symptoms of diabetic complications began to creep into his life, including worrying heart palpitations. When a doctor diagnosed him with retinopathy, it was a wake-up call that convinced him he needed to make changes.
His search led him to the writing of low-carb advocates Dr. Richard Bernstein and Dr. Keith Runyan, and Dr. Lake soon adopted a ketogenic diet: “And I managed to get perfect blood sugar control immediately. And I’ve never looked back since, really. My blood sugar has always been in the non-diabetic range since then.”
In recent years, he’s also experimented with intermittent fasting. Like many, he was turned onto the concept by reading the work Dr. Jason Fung. “I’d always known that diabetes control is so much easier when you don’t have to take insulin [for food].” It started with skipping breakfast, which was always the trickiest meal of day for his glycemic management. “I sort of figured that if I missed breakfast, things would just be better.”
Emboldened by the good results he got from skipping breakfast, Dr. Lake moved up to 24-hour fasts, to 72-hour fasts and, eventually, a remarkable seven day fast. That was a “sedentary” fast, but he went for a long run on the 7th day, some 150 hours since he had last eaten a meal, and “it was fantastic.” Since that time he’s almost exclusively exercised in a fasted state, with only basal insulin on board.
That brings us to the ZeroFive100 Project, which Dr. Lake conceived of as a way to anecdotally but impressively demonstrate the safety and efficacy of the ketogenic diet for people with or without diabetes. If you’re wondering what fasted distance running has to do with keto, think of it this way: the keto diet is intended to push the body to state of “fat-adaption,” in which the metabolism prefers burning fat to carbohydrates. By running 100 miles in five days without eating, the body pushes ketogenic fat adaption to the limit—during the course of the event, each runner needed to utilize about 20,000 calories entirely from stored body fat. (And yes, they did all lose weight).
Of course, there’s a point at which fasting becomes dangerous, and we begin to call it starvation. Dr. Lake chose five days because it was extreme enough to be attention-grabbing but not quite extreme enough so as to actually pose a danger to himself and the other runners. The runners submitted themselves to a battery of daily tests to assess their metabolic and respiratory health. Several runners, both with and without diabetes, used continuous glucose monitors.
Remarkably, several of the runners experienced notable drops in blood sugar during the course of the event; one runner (who did not have diabetes) was actually in a traditionally defined state of hypoglycemia for as much of a third of the time, but showed zero symptoms. Dr. Lake finds that these results, although from an admittedly very small and unusual sample, suggest that “low blood glucose in fat burning is a safe metabolic state.”
Hypoglycemia, of course, remains incredibly unsafe for people with Type 1 diabetes no matter what they have or haven’t eaten, and throughout the race Dr. Lake and the other runner with Type 1 diabetes did not hesitate to correct their hypos. (This also means that Dr. Lake actually consumed slightly more than zero calories.) But anyone that has guzzled juice or gobbled enormous amounts of candy during strenuous cardiovascular exercise might be shocked at how little glucose they required throughout the event, a handful or two of sweets, which demonstrates how definitively their bodies preferred fat as fuel. Meanwhile, Dr. Lake’s basal insulin requirements “plummeted” down to some 25% of his usual dosage.
All told, the run was a success. All of the participants, who had varying levels of experience both with running and with fasting, finished. All reported high levels of energy and low levels of hunger (especially after the first 48 hours).
Dr. Lake doesn’t want the average patient with diabetes to stop eating and start running marathons. The point of the project wasn’t to demonstrate the wisdom of long fasts and intense exercise, which almost certainly should not be practiced without direct medical supervision. Rather, it hopes to argue that if this extreme stunt is healthy and safe, much smaller decisions—skipping breakfast, or eating very few carbs in the context of an otherwise nutritional diet—must be even safer.
“I hoped to prove that: one, you do not need sugar for energy. Two, you do not need to eat carbs if you’re taking insulin, as long as you’re not experiencing a hypo. And three, nutritional ketosis will not lead to diabetic ketoacidosis.”
Dr. Lake has launched a new website—Type1Keto.com—a new platform for his effort to convince doctors and patients alike that the ketogenic diet should be an option for all people with diabetes.