According to conventional wisdom, type 2 diabetes (T2D) is a progressive and irreversible disease. Glycemic control typically worsens over time, with patients being put on ever higher doses of oral medication until those are no longer sufficient, at which time they’re started on insulin injections, with these, too, increasing in dose over time. And unfortunately, insulin is hardly without its own list of adverse effects, including weight gain, hypoglycemia, increased mortality, and increased risk for certain cancers.

Patients with T2D deserve better. They deserve to know that it’s possible to lower blood sugar and even eliminate the need for several medications through changes to diet and lifestyle. A new case report on the use of therapeutic intermittent fasting lends weight to the impressive body of evidence that people with T2D can achieve better glycemic control and have lower HbA1c while using less medication, and in some cases, no medication at all. That’s right: better blood sugar despite using less medication.

The paper, Therapeutic use of intermittent fasting for people with type 2 diabetes as an alternative to insulin, published in BMJ Case Reports, details three male patients with T2D who undertook a fasting regimen. The men were age 40, 52, and 67 and had been living with T2D for 20, 25, and 10 years, respectively. The fact that they’d been diagnosed a minimum of 10 years prior is noteworthy, because it shows that this kind of improvement is not limited to newly diagnosed diabetics. All three men were on insulin (at least 70 units daily) and had comorbidities of hypertension and hypercholesterolemia, with one subject also having chronic kidney disease and a history of renal cell carcinoma.

For the fasting, two subjects fasted 24 hours 3 times a week (one for 7 months, one for 11 months), while the third fasted on alternate days for 11 months. On fasting days, foods containing significant calories were prohibited but subjects could consume unlimited amounts of water, coffee, tea, and broth. (A daily multivitamin supplement was encouraged.) On eating days, subjects were encouraged to follow a diet low in sugar and refined carbohydrates. 

The results were impressive. All three subjects were able to completely discontinue insulin injections—one within just 5 days, one after 13 days, and one after 18 days. (Subjects measured their own blood glucose at least 4 times daily during the weaning period.) Not bad: less than three weeks to eliminate the need for a medication that is expensive and reduces quality of life. In fact, all diabetes medications were eliminated except for one subject who continued on canagliflozin.  

Even though medications were eliminated, these subjects had better glycemic control. HbA1c went from 11 to 7 in one subject; from 7.2 to 6 in another, and from 6.8 to 6.2 in the third. And yes, 7, 6, and 6.2 are still high, but two of these subjects went from full-blown T2D (A1c > 6.5) to pre-diabetes (A1c 5.7-6.4). This kind of improvement is nearly unheard of. The study authors wrote, “Medications help manage the symptoms of diabetes, but they cannot prevent the progression of the disease.” The intermittent fasting regimens in these case reports not only stopped progression, in that A1c didn’t worsen, but they actually reversed the progression. Instead of getting higher, A1c got lower.

Having only 3 subjects, this was a very small study, but the findings that people with T2D can experience better glycemic control while on fewer medications—and in some cases, no medications—echo those of a larger study that showed improvements in several parameters of diabetes and cardiometabolic risk among subjects with T2D who followed a ketogenic diet. Fasting isn’t the same as a ketogenic diet, of course, but ketogenic diets induce some of the same metabolic effects, in particular, reductions in blood glucose levels and endogenous insulin secretion.

This novel study shows that substantial improvements in T2D management can be realized with a very low-level (and free!) intervention like intermittent fasting. And it should be emphasized again that these improvements were above and beyond what the subjects had achieved with pharmaceutical therapies. The authors stated, “Therapeutic fasting is an underutilised dietary intervention that can provide superior blood glucose reduction compared with standard pharmacological agents.”

The published paper doesn’t provide information regarding whether subjects actually adhered to a lower carbohydrate diet on their eating days, nor how strictly they adhered to their fasting schedules. It can’t be determined how much—if any—of the glycemic improvement may be due to the dietary change, and how much to the fasting. Nevertheless, it’s clear that all subjects’ blood glucose control improved substantially while using fewer or no diabetes drugs, and they all also lost weight (from 9 to 10.6kg lost) and reduced their waist circumference (by 13-19cm).   

More research is needed regarding the efficacy of various fasting regimens for improving T2D, but as interest in fasting grows among physicians and laypeople alike, we will likely see more case reports like this being published. When the alternative is medications that are expensive and bring lists of undesirable and sometimes dangerous side-effects, it’s important that patients are educated, empowered, guided and supported with implementing lifestyle and dietary changes that seem to be far more promising.     

By Amy Berger, MS, CNS