Zero Five 100 Fasted Challenge

By Claire McDonnell Liu, Nutritionist (@LeafieHealth)

100 miles, in 5 days, while fasting

The Zero Five 100 Fasted Challenge team of 8 ran or walked the 100 mile distance between Henley and Bristol, England, over a 5 day period. Each participant took in zero food, only water, electrolytes, multivitamins and the occasional black coffee for some. ZERO CALORIES!!

Dr Ian Lake, an English GP with Type 1 Diabetes, devised the unique Zero Five 100 Fasted Challenge. The project explores the physiological effects of fat adaption and ketosis in people with and without Diabetes Type 1 during prolonged exercise.

The Challenge team

The Challenge team consisted of: Olympic gold medallist James Cracknell; Steve Bennett, Jake Thompson; (Type 1 Diabetic ) Jon Furniss., Dr Ian Lake (Type 1 Diabetic),;Dr Ali Ibrahim (Phycologist); Diabetes Nurse Gayle Gerry; Dietician Trudi Deakin.

All Zero Five 100 Fasted participants completed the 5 day fasted endurance challenge feeling good with energy to continue. Participants represented ages from 29 to 62, both sexes, 2 with type 1 diabetes, 1 obese person, 1 professional athlete and a health author.

Each participant had metabolic, blood and body composition measurements taken each morning and at rest periods.  Results demonstrated that all participants were able to access stored body fat throughout the project whilst resting metabolic rate remained consistent. Significantly the blood glucose levels of all participants remained within normal physiological ranges, showing less than 39% variation for each individual. 

Watch the Zero Five 100 Fasted Challenge

Watch the Zero Five 100 Fasted Challenge documentary to see how the team adapted to meet and exceed expectations.

Dr Ian Lake said: ‘I find it difficult to accept that a safer and superior option for managing Type 1 Diabetes is not routinely provided as an option for patients. It is up to the  patients to weigh up their options and choose what suits their needs at the time. We are failing to provide treatment options and that can’t be right. Clinicians legitimate concerns about safety hinder reasoned scientific argument. I think we have answered most of those concerns in a five day challenge. Keto is a safe option for people with Type 1 diabetes’.

‘Sugar is not the preferred fuel of the body in aerobic metabolism. 


If a person is exercising sugar is utilised for energy as a priority, or it will be converted to glycogen and fat. I would argue that although sugar is used up ahead of fat (if available in a free form), it is not preferred. As alcohol is prioritised over glucose for metabolism, that does not mean alcohol is the preferred fuel’.

‘Fat stored in the adipose tissue is the fuel tank and not the food in the stomach. We set out with this project  to explore the potential of that fat tank by draining down 20,000 calories in a natural and physiological way. I had an 86,000 calorie supply on board at the end of the five day challenge’.

‘Subsequently we have have demonstrated beyond doubt that diabetic ketoacidosis from nutritional ketosis is not the case’.

The LCDU Type 1 Diabetes Course

A Low Carb, High Fat diet can be used to manage Diabetes Type-1 and Diabetes Type-2. There is growing interest in returning to carbohydrate restricted diets to manage diabetes complications and provide longterm control.

If you have Type-1 or Type-2 Diabetes it is important to understand the relationship between consumption of carbohydrates and blood glucose control.

Always seek medical advice before beginning dietary changes.

Low Carb Down Under provides an online Type 1 Diabetes Course. Follow our course helping people living with type 1 Diabetes to better understand the LCHF approach to managing Type-1-Diabetes.

Type 1 Diabetes Presentation

A well formulated LCHF diet can help Type-1 and Type-2 Diabetics achieve long term normalised blood sugar levels. For more resources on LCHF and Diabetes we recommend research by Dr Richard Bernstein; Dr Jason Fung; Dr. Troy Stapleton; Lisa Scherger; Dr. Wendy Pogozelski. Find out more about the Low Carb nutritional therapy for Type 1 diabetes with Dr Troy Stapleton’s recent talk.