Medically Reviewed by Ana Reisdorf MS, RD on January 25, 2020.
Diabetes is widespread in both the United States and Canada and is one of the leading causes of death.
The American Diabetes Association reports that treating diabetes costs over 200$ billion per year.
Type 2 diabetes is the most common type. The condition affects the body’s ability to produce insulin, which regulates blood sugar levels.
Changes in lifestyle, such as change of eating habits play a crucial role in managing the disease.
Following specific diets, such as intermittent fasting, for those with diabetes is often recommended by the doctors.
Let’s answer the most common questions we get from our customers and dig a little deeper into the science!
So is it OK for diabetics to fast?
The answer is YES, but it has its exceptions.
People with advanced diabetes or who are on medications for diabetes shouldn’t attempt intermittent fasting unless under the close supervision of a physician who can monitor them.
When it comes to taking medications, no one argues, that the doctor is the one who should prescribe them. When it comes to a change of diet, people tend to improvise without considering the possible consequences.
So it’s only natural, that drastic changes in one’s diet also shouldn’t be hidden from the doctor, especially when diabetes is so nutrition-related.
Intermittent fasting is a form of therapeutic treatment. Since your doctor knows your disease history better than anyone else, he or she should be the first one you consult! Although the doctor would most likely approve your fasting, together with giving you directions on how to do it correctly.
Is fasting good for Type 2 Diabetes?
This article itself is based on studies of type 2 diabetes.
Case studies have shown that intermittent fasting has helped people with this condition to limit their insulin intake, dramatically lower insulin levels and significantly improve insulin sensitivity, as well as significantly lower blood pressure.
Some people started controlling their blood sugars so well with the food they eat, they stopped taking medication at all, although it’s not that easy to achieve.
Can fasting increase your blood sugar?
Intermittent fasting actually reduces your blood sugar and improves your insulin sensitivity. When a person doesn’t eat (doesn’t consume sugar/carbohydrates), it is only natural that sugar levels drop.
When you’re on your fasted state and have less glucose available for fuel, the body relies on stored body fat as an energy source. So you both improve your sugar levels and burn fat while you’re fasting.
Can a diabetic fast for 3 days?
As some case studies have proven – yes. And the results can surprise you. Let’s dig in the study thoroughly.
The case we’re talking about documents a 69-year-old man who is diagnosed with type 2 diabetes (T2D) for 35 years. Before starting intermittent fasting patient was taking 160 units of insulin daily and 1000 mg of Metformin twice a day to manage his disease.
The patient has been on Metformin for 35 years and on insulin treatment for the past 11 years. He has never used any other forms of diabetic medication.
Before the treatment, he attended an initial 6-h nutritional seminar outlining the basics of a low-carbohydrate diet and intermittent fasting, as well as an introduction on the topics of obesity, T2D, fasting, body composition, insulin resistance, and meal timing.
The initial fasting prescription introduced a 24-h fast, three times a week. In addition, he reduced his dietary intake of sugars and refined carbohydrates and increased his consumption of natural fats. The patient was instructed to consume approximately 70% of his daily calories from natural fats, 20% from proteins (both plant and animal-based) and 10% from net carbohydrates (leafy greens and non-starchy vegetables).
He would drink water, non-sugared tea, black coffee, and homemade bone broth.
One month into the treatment, as the patient began feeling more confident with the program, he requested that his fasting period should be extended and began fasting between 24 and 36h, three times a week. After the second month, he again pushed his fasting schedule to between 24 and 42 h, two to three times a week.
On eating days, he ate in two 90-min eating windows. The 24h fasting protocol consisted of fasting between dinner on a certain day and the dinner on the next day. The 36h fasting protocol consisted of fasting between dinner on one day and breakfast 2 days later. The 42h fasting protocol consisted of fasting between dinner on one day and lunch 2 days later.
This sure is an extreme pattern, but it is possible. A physician and a dietary counselor monitored the patient every 2 weeks until insulin was discontinued, after which he was followed monthly. The patient tested his blood sugar four times daily during the insulin-weaning period. Target daily blood sugars were between 7 mmol/L and 10 mmol/L.
Food diary, blood sugar log, and adherence to fasting schedules were discussed at each visit. The team made adjustments to fasting regimen and medication dosage. In addition, the patient’s weight, waist circumference, and blood pressure were measured and recorded at each visit.
Over the 4 months of treatment, the patient’s weight decreased by 17.8% (from 204 lbs to 167 lbs) and waist circumference by 11% (from 42.9 in to 38.1 in)
Further into how intermittent fasting helps with diabetes
Our metabolism has adapted to daytime food, nighttime sleep.
Nighttime eating is well associated with a higher risk of obesity, as well as diabetes. That’s why it is highly recommended to follow an intermittent fasting plan and avoid eating at night or very late evenings.
Generally explained, a higher-than-normal blood sugar level puts you at risk for developing diabetes and heart disease. Intermittent fasting (IF) helps to balance out blood sugar and insulin. IF can reduce blood sugar by 3-6% and insulin levels by 21-30%.
The University of Alabama conducted a study with a small group of obese men with prediabetes. They compared a form of intermittent fasting called “early time-restricted feeding,” where all meals were fit into an early 8 hour period of the day (7 am to 3 pm), or spread out over 12 hours (between 7 am and 7 pm).
Both groups maintained their weight (did not gain or lose) but after 5 weeks, the 8-hours group had dramatically lower insulin levels and significantly improved insulin sensitivity, as well as significantly lower blood pressure. The best part? The eight-hours group also had significantly decreased appetite. They weren’t starving.
Just changing the timing of meals, by eating earlier in the day and extending the overnight fast, significantly benefited metabolism even in people who didn’t lose a single pound (not losing weight can be related to eating the same amount of calories in their 8-hour eating window as they normally would).
Another study was conducted in Canada and showed even greater results.
Before the study, three men with type 2 diabetes attended nutrition seminars, which gave them information regarding the development of the condition, its effects on the body, and how to use diet to manage diabetes (same as in the first case study mentioned).
After attending nutrition seminars, two men were asked to fast for 24 hours every other day, while the third fasted for 3 days each week. During fasting days, the men could drink low-calorie beverages such as water, tea, or coffee. In addition, they could eat a low-calorie meal in the evening. This regime may sound a little harsh, but the men were always on the supervision of scientists, who made sure they were all feeling fine.
The trial lasted 10 months in total, and the three men stuck to their schedule without encountering any difficulties. After the fasting period, the team measured their weight and blood glucose.
The results revealed significant improvement: all three lost weight, blood glucose was lower, and they were able to stop using insulin after a month from the beginning of the trial. In one case, the person stopped after only 5 days. Two of the men also discontinued all diabetic drugs, while the third participant stopped 3 out of 4 drugs.
The authors concluded that intermittent fasting may help people with diabetes, but the study was limited to three participants.
More research is needed to confirm these findings, but they are encouraging and intermittent fasting surely shouldn’t be overlooked as a form of therapeutic treatment.
People with advanced diabetes or who are on medications for diabetes, people with a history of eating disorders like anorexia and bulimia, and pregnant or breastfeeding women should not attempt intermittent fasting unless under the close supervision of a physician who can monitor them.