Ordinary calorie restriction through any diet can lead to weight loss and make it easier to manage blood sugar. Intermittent fasting is thought to go a step further by lowering serum insulin, which triggers the body to burn stored sugar, called glycogen, along with fat, in the absence of glucose from food, Dr. Fung says. These processes (called glycogenolysis and lipolysis, respectively) can temporarily lower blood sugar and cause weight loss.
How Intermittent Fasting Affected Men in the Study
In the study, Fung and his team randomly recruited three men, ages 40 to 67, with type 2 diabetes, who also had high cholesterol and high blood pressure. At the start of the study, the authors recorded the participants’ vitals, including their A1C (a three-month average of their blood sugar levels), their fasting blood glucose levels, their waist circumference, and their weight. All three men were on insulin and oral medication.
The men took a six-hour educational course on diabetes and intermittent fasting prior to fasting. For the experiment, one man fasted for 24 hours three days per week, and the other two alternated their fasting days throughout the week. On fast days, they ate one low-calorie meal in the evening, and drank low-cal beverages, such as water, coffee, tea, and broth. The authors encouraged participants to opt for low-carb on the eating days.
Two times per month, Fung and his colleagues observed the participants, and adjusted their insulin and medication to help prevent episodes of hyperglycemia and hypoglycemia (low blood sugar).
Eighteen days into the study, all three men lost 10 to 18 percent of their body weight, trimmed their waist circumferences, no longer had to take insulin, and reduced their oral medication. (Two of the three men completely got off their medication during this time frame.)
“In all cases, their blood sugar was actually better at the end than the beginning despite not taking medication, which tells you the diabetes is reversing,” says Fung, adding that the participants maintained their improved vitals for about a year total.