The first physician to develop fasting protocols for treating diabetes was most likely G. Guelpa, a French physician. He detailed his experience in his 1912 book Autoin-toxiecation and Disintoxication, in which he discussed using fasting to treat diabetes and a variety of other conditions such as sciatica, obesity, pulmonary diseases, alcoholism, and melancholia (depression).
Guelpa had an interesting fasting regimen which included drinking Hunyadi János, a natural purgative mineral water drawn from Saxlehner’s Bitterwater Springs near Budapest, Hungary. Guelpa recommended the entire abstinence from food for three days, during which time the patient could drink water, weak tea, and one bottle of Hunyadi János daily. After the fast, Guelpa had patients drink milk for one week, followed by a second fast of three to four days. The second fast would be broken with coffee or tea for breakfast, and clear soup, salad, and apples or pears for lunch and dinner.
From 1915 until the discovery of insulin in 1922, American physicians Frederick Madison Allen and Elliott Proctor Joslin advocated water-only fasting as a treatment for diabetes based on the work of Guelpa. Allen and Joslin treated primarily diabetic children and severely afflicted adults.
Elliott Proctor Joslin was the first doctor in the United States to specialize in diabetes and was the founder of the Joslin Diabetes Center, still in operation today. He was the first to advocate for teaching patients to care for their own diabetes, an approach now commonly referred to as Diabetes Self-Management Education. In 1908, in conjunction with physiologist Francis Gano Benedict, Joslin carried out extensive research examining the fasting and feeding of patients who had diabetes.
In 1984, Scandinavian researchers found that treating obese type II diabetes patients with fasting and calorie restriction (200 calories per day) led to the normalization of blood glucose and the disappearance of urinary glucose. Other findings included the reduction of fasting serum insulin concentrations by 54%, serum triglycerides by 65%, serum cholesterol by 28%, and high density lipoprotein by 14%. The researchers concluded that “Supplemented fasting appears to be a safe and useful tool in the treatment of obese type II diabetics.”