Intermittent Fasting - Just Another Fad Or Therapeutic Treatment?

​Wei Perng, PhD

“What can you do with three diabetics?” This past fall, I attended a conference and ran into a favorite mentor. He keeps up with the latest studies and the first thing he said to me was, “What can you do with three diabetics?” I was confused – not sure if it was a joke or a hypothetical question. He went on to tell me about a hot-off-the-presses study in BMJ Case Reports that demonstrated the effectiveness of intermittent fasting to improve glucose control for three patients referred to a dietary management clinic. 

This dietary regimen involves eating within a specified period of time and fasting at all other times (e.g., eating during 24 period and fasting the day after). Patient #1 was a 40-year old man who suffered type 2 diabetes for 20 years, along with high blood pressure (hypertension) and high cholesterol (hypercholesterolemia). Patient #2 was a 52-year-old man with a 25-year history of type 2 diabetes, in addition to chronic kidney disease, renal cell carcinoma, hypertension, and hypercholesterolemia. Patient #3 was a 67-year old man diagnosed with type 2 diabetes 10 years ago, along with hypertension and hypercholesterolemia. All three men were on insulin prior to the start of the study. The primary intervention was dietary education and medically-supervised therapeutic fasting that involved alternating 24-hour fasts. On fasting days, the men were allowed unlimited amounts of low-calorie fluids (e.g., coffee, tea, water, bone broth) and only consumed dinner. On non-fasting days, they skipped breakfast but consumed lunch and dinner. The investigators evaluated the patients’ glycemic control and other diabetes-related measures (lipids, blood pressure, waist circumference, weight) on every two weeks. In addition to improved glycemic parameters and weight loss, all three men were able to stop taking insulin, with one patient weaning as early as 5 days after starting the intermittent fasting regimen. Additionally, none of the patients had episodes of hypoglycemia or other adverse health outcomes. Although additional studies are needed in larger samples and more diverse populations, results of this case study suggest that intermittent fasting helps to reverse type 2 diabetes and minimize use of pharmacological and/or surgical interventions in diabetes patients.
What about the general population? Would the rest of us benefit from intermittent fasting? Maybe but this is still unknown. While it’s not necessary for the average person (i.e., non-overweight/obese, non-diabetic, no chronic conditions) to fast for such long periods of time, a less extreme form of intermittent fasting can simply be to avoid snacking between meals or to use an extended overnight fasting (e.g., not eating after 7 pm). Just a few years ago, dietitians recommended frequent consumption of small meals throughout the day to keep up one’s metabolism. However, we now know that continuous grazing leads to chronic stimulation of insulin secretion, which in turn, can lead to weight gain. By eating discrete well-spaced meals, we allow insulin and glucose to return to baseline levels, which is also beneficial to other aspects of metabolism. Stay tuned!