Fasting and Diabetes

Fasting and Diabetes

There are a lot of controversies regarding the effect of fasting on people with diabetes. It entails diabetes patients depriving themselves of food for a certain period to improve their blood glucose levels. More commonly, it is done for dietary reasons, to lose weight and restrict calorie intake.

Although the body usually enters its fasting state eight hours after the last meal, fasting impacts are determined by the actual duration of the fast and the type of diabetes a person has. While fasting can potentially improve the health status of individuals with type 2 diabetes, the case is different for type 1 diabetics.

In a bid to resolve the current debate on the safety of fasting in diabetics, we pulled together available research on fasting and diabetes. Hopefully, this will influence your decision the next time you decide to take a hiatus from food.

Is It Safe for Diabetics to Fast?

Fasting without proper consultation of a health specialist can present some risks to diabetic health. The following section highlights the major ones.


Risk of Hypoglycemia


Hypoglycemia is one of the significant risks associated with fasting while on anti-diabetic medication. When induced by fasting, this condition is termed Fasting-Evoked En-route Hypoglycemia in Diabetes (FEEHD). In one survey that examines the prevalence of FEEHD in diabetes patients, 27.1% of the sample population reported having at least one FEEHD event, with a meager 31.1% of these patients informing their health provider of such events.


Possible Risk of Ketoacidosis


A ketogenic diet is a common trend among people with diabetes looking to shed weight fast and boost energy levels. It generally entails a strict diet regimen of low carbs, high fat, and adequate protein.

However, research proves that when this type of dieting is combined with fasting, it can lead to a state of ketoacidosis with symptoms ranging across fatigue, nausea, and vomiting. This was the case of a 60-year-old male diabetic and ketogenic diet follower who engaged in prolonged fasting.

Although he noticed considerable weight loss and improved glycemic control at first, he reached the breaking point when he decided to forgo food and live on just water in a bid to fast-track his transition into ketosis. Following a five-day fast, the intake of soup and chlorophyll supplement prompted nausea, vomiting, and dizziness in the patient. Based on these findings, the combination of fasting and a keto diet isn’t advised in people with diabetes.


Reduced Blood Glucose Levels 


It is a common hypothesis that prolonged fasting, due to a reduction of calorie intake, positively affects blood glucose levels directly or indirectly. However, recent research exposes new information on the effect of fasting on people with diabetes.

Research centered on the effect of fasting duration on blood glucose levels proves that individuals without diabetes had reduced blood glucose levels irrespective of the fasting length. Notably, there was a negligible difference in blood glucose in patients that fasted for eight hours and those who fasted for three hours. This eliminates the need to fast for more extended hours since you can get similar, healthier results in shorter periods.

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Tips to Help You Pull Through Fasting as a Diabetic

When fasting, your chances of developing hyperglycemia are just as high as those of developing hypoglycemia. Hence, it’s reasonable to take some precautions to prevent complications. Here are some of them:

  • You should check your blood glucose levels more often while fasting.
  • Continue a varied and balanced diet.
  • Communicate your diet plan and medications with your physician if you plan on fasting.
  • Introduce low glycemic index (GI) foods into your diet to prevent blood glucose spikes.
  • Following the break of fast, be sure to drink lots of decaffeinated and zero-sugar drinks to prevent dehydration.
  • Stay away from too many sugary and fatty foods, as this may counter the effects of your fasting.


Fasting is recommended for people with diabetes and those without it, mainly to lose weight. Judging by the available studies on fasting and diabetes, it is clear that fasting does present a few benefits, including lowered blood sugar levels. However, its risks may outweigh its benefits when paired with specific meal plans (e.g., ketogenic diets). Hence, it’s advised you consult with your health provider before embarking on fasting, especially if you are a keto diet follower.

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