Dr. Alba,
Why is it said that diabetics (Type 2) should keep eating at regular intervals?
What will be the effect of prolonged fasting (say 24 hours or so) on a person in the prediabetic range who is not taking conventional diabetes medicine but is using naturopathy?
Shouldn't the lack of food keep reducing the sugar level in the blood? Will the effect be different if the person is controlling blood sugar with medication?
— Varun
A 24-hour fast does not automatically keep lowering blood sugar. When you stop eating, the liver can release stored glucose and make new glucose to help keep the brain and other organs supplied with energy. Some people with prediabetes or type 2 diabetes can use intermittent fasting safely, but prolonged fasting is not appropriate for everyone. The biggest concern is often medication: insulin and certain glucose-lowering medicines can substantially increase the risk of hypoglycemia during fasting.
Not necessarily. Advice to eat at fixed intervals was traditionally important for people using insulin or medicines that could cause hypoglycemia. Modern diabetes treatment is more individualized. Some people do well with three regular meals, while others may safely use a longer overnight fasting period or another structured eating schedule.
What matters is the person's diabetes treatment, glucose pattern, nutritional needs and overall health. If you are trying to understand your own readings, see our blood sugar level chart and our guide to fasting blood sugar levels.
This is an excellent question. Food is not the body's only source of blood glucose.
When you have not eaten for several hours, insulin levels generally fall and the liver helps maintain blood glucose. It can release glucose stored as glycogen and can also make glucose from other substances through a process called gluconeogenesis.
This is why fasting glucose does not simply continue falling toward zero. The body has regulatory systems designed to maintain an adequate glucose supply.
In people with insulin resistance or type 2 diabetes, the liver may release more glucose than is needed. This is one reason someone can wake with an unexpectedly high glucose level despite having eaten nothing overnight. Our insulin resistance guide explains this process in more detail.
The response varies considerably from person to person. Glucose may decrease in some people, remain relatively stable in others, or sometimes rise because of liver glucose production, stress hormones, illness, dehydration or inadequate diabetes treatment.
Intermittent fasting and time-restricted eating are being studied as possible approaches to weight and glucose management in type 2 diabetes. They are not automatically dangerous, but neither are they a diabetes cure. The overall eating pattern, calorie intake, weight change, medications and ability to maintain the approach safely all matter.
A person with prediabetes who is not taking glucose-lowering medication generally has a much lower medication-related risk of hypoglycemia than someone using insulin or certain diabetes drugs. That does not mean a 24-hour fast is automatically appropriate.
For prediabetes, the larger priorities are usually sustainable nutrition, physical activity, weight management when appropriate, sleep and monitoring of glucose or HbA1c. Learn more in our guide to blood tests used for diabetes and prediabetes.
This is where Varun's final question becomes especially important. Different diabetes medicines behave very differently during fasting.
This is why someone taking diabetes medication should not simply begin a 24-hour or prolonged fast and continue medication unchanged without discussing the plan with the healthcare professional managing the treatment.
If blood glucose falls below 70 mg/dL (3.9 mmol/L), it is considered clinically important hypoglycemia and should be treated rather than continuing a fast. Severe weakness, confusion, fainting, seizures, persistent vomiting, dehydration, or symptoms suggesting diabetic ketoacidosis require urgent medical attention.
I would separate this from the question of fasting. Herbal or “natural” products are not automatically safe simply because they are natural. Some may affect blood glucose or interact with medications, and evidence for many products marketed for diabetes remains limited.
A person using supplements or herbal remedies should tell their healthcare professional what they are taking, particularly when combining them with diabetes medication. See our overview of diabetes and supplements.
You were correct to question the idea that not eating must continuously drive blood sugar downward. The body can maintain blood glucose during fasting by releasing and producing glucose, particularly through the liver.
Some people with prediabetes or type 2 diabetes may be able to use intermittent fasting safely. The important question is not simply “Is fasting good or bad for diabetes?” but rather “Is this type of fasting safe and appropriate for this particular person, with this medication and health profile?”
American Diabetes Association. Standards of Care in Diabetes—2026. Diabetes Care. Guidance on fasting emphasizes individualized risk assessment, glucose monitoring and medication management.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Fasting Safely With Diabetes.
Diabetes UK. Intermittent fasting diets for type 2 diabetes remission and guidance on fasting with diabetes.
Medical note: This answer provides general education and does not replace individualized medical care. Anyone with diabetes who plans prolonged fasting should discuss medication and glucose-monitoring needs with their healthcare professional.