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Intermittent Fasting an Effective Way to Manage Type 1 Diabetes? Find Out What Research Says

« WeCare Blog | June 7, 2021 |
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Intermittent Fasting an Effective Way to Manage Type 1 Diabetes? Find Out What Research Says

With so many diets in the market that claim to help you achieve better health than ever, it is normal to wonder whether it might also help you manage your type 1 diabetes. 

One of the diets that has increased the interest of many people living with type 1 diabetes is intermittent fasting. In this article, we give you an overview of intermittent fasting. We provide you with a summary of the research done on the use of intermittent fasting for diabetes management. Finally, we will tell you what experts say regarding the safety and effectiveness of intermittent fasting if you are living with type 1 diabetes. 

What Is Intermittent Fasting?

Intermittent fasting is an eating plan where people have long periods of fasting and shorter eating periods on a regular schedule1. Unlike most eating plans that focus on what a person should and shouldn’t eat, intermittent fasting prioritises when to eat1
It is based on the premise that during fasting periods, the body exhausts its sugar stores, insulin levels go down and starts burning fat. This is referred to as metabolic switching.

The typical western lifestyle could be as follows: a person eats several calorie-rich meals from the early morning to late at night and does not exercise, their glucose and insulin levels spike, and they gain fat. Every time you eat, you’re running on those calories and not burning your fat stores. Over time, that lifestyle increases the risk of health problems, like obesity, type 2 diabetes, and problems with the immune system2.  

Intermittent fasting contrasts with the western-style diet, as it restricts when a person can eat. There are three main approaches to intermittent fasting.1

  • Daily fasting: In a day, there are several hours where a person does not eat or drink anything with calories. The fasting period usually extends from 16 to 18 hours. Then, there is a shorter period, between 6 and 8 hours daily, where a person can eat.  
  • 5:2 fasting: A person eats normally for 5 days and then has two days a week to only eat one meal a day or restrict calorie consumption between 500 and 800 on those two days. 
  • Complete daily fasting: A person abstains from food entirely for one to three days. This type of fasting can be dangerous and is not recommended. 

Risks and Benefits of Intermittent Fasting In Type 1 Diabetes Management

Because of the beneficial impact of intermittent fasting on weight, glucose and insulin levels in people not living with diabetes, researchers have had a growing interest in using this eating plan as therapy for people living with diabetes. 

However, most studies have focused on the impact of intermittent fasting on people living with type 2 diabetes rather than type 1 diabetes. 

The limited number of studies that have looked at the impact of intermittent fasting on type 1 diabetes have suggested that it may promote weight loss and insulin sensitivity.3  There have been animals studies carried out  to investigate the impact of intermittent fasting on the regeneration of damaged pancreatic cells in type 1 diabetes mouse models. Further studies in this area are needed.

However, even with the potential benefits of intermittent fasting for people living with diabetes, one should be aware of the potentially serious risks for diabetes management and health in general. Some of the risks include 3

  • Increased risk of dehydration since fasting people tend to eat fewer foods with water content, like fruit, and some people may be taking medications that promote water loss. 
  • Increased risk of hypoglycaemia in people on insulin. This happens when a people do not modify their insulin schedule, but their eating schedule has changed. Remember that insulin is the hormone that is responsible for getting glucose into the cells. But when a person isn’t eating, there isn’t a steady supply of glucose from the diet, so glucose levels can dip dangerously low if appropriate adjustments to insulin doses are not made. 
  • An increased risk of ketoacidosis if your body tries to compensate for low glucose levels by breaking down fat stores, or if insulin is reduced too much when your diet is adjusted4

Researchers have demonstrated that intermittent fasting can be beneficial to people living with type 1 diabetes when they are part of continuous, structured education programmes that help them adjust to their lifestyle, medication, and monitoring. However, many people living with type 1 diabetes do not have these support programs as an option. 5  

Do Experts Recommend Intermittent Fasting to Manage Type 1 Diabetes?

While initial research on the use of intermittent fasting as a therapy for type 1 diabetes management is promising, diabetes expert organisations, including Diabetes UK and the American Diabetes Association, have not put out statements recommending or advising against using intermittent fasting. 
This is because more research is needed to understand its effects and safety, and because intermittent fasting doesn’t work as a blanket strategy for everyone.7

Tips If You Choose to Do Intermittent Fasting While Living With Type 1 Diabetes

There are no medical guidelines on how to use intermittent fasting for diabetes management. A team of diabetes experts has reviewed the research to recommend guidelines to people living with diabetes who choose to follow an intermittent fasting eating plan.3

  • Keep a close watch on your blood glucose to prevent it from getting too low, including considering a continuous glucose monitoring system. 
  • Learn about the symptoms of hypoglycaemia, so you are prepared to notice them in case they arise.
  • If you are using an insulin pump, be prepared to discuss insulin timing and dose adjustments with your diabetes healthcare team. Grajower et al suggests “Patients on an insulin pump should initially reduce their basal rate by 10%, with further adjustments based on frequent (every two hours) blood glucose testing that continues until a stable pattern is established. It is not unusual with a full day fast to encounter a need for the basal rate to be reduced by as much as 90% towards the end of the fasting day in a patient with type 1 diabetes. The pattern of measurement and repeated adjustment should be followed throughout the fast to ensure safety.”3
  • Be prepared to be flexible with your eating window if your blood glucose dips too low. 
  • Maintain close contact with your healthcare team, and work with a dietitian to ensure that you meet your dietary needs throughout the day and that your eating windows and fasting windows meet your body’s needs. 
  • Don’t rush it. There is a time period where your body is adjusting to new eating patterns. Even in people not living with type 1 diabetes, the adjustment period can take up to 3 weeks1. People living with type 1 diabetes must be patient to ensure their body is able to provide a steady supply of glucose, and that you are adjusting your insulin treatment accordingly.  

Final Thoughts

You may be tempted to try different eating plans to see if it improves your health and makes it easier to manage life with type 1 diabetes. However, at this stage there is not enough evidence to recommend the use of intermittent fasting for people living with type 1 diabetes because the risks are high, and the benefits can generally be achieved with other eating and exercise plans. 

If you do choose to follow an intermittent fasting eating plan, make sure that you educate yourself on how to identify and monitor unexpected changes in glucose, but, most importantly, work with your healthcare team to create a management plan, including lifestyle and medication changes. 

1.    Intermittent Fasting: What is it, and how does it work? Available at: Published 2020. [Accessed March 2021].
2.    Christ A, Latz E. The Western lifestyle has lasting effects on metaflammation. Nature Reviews Immunology. 2019;19(5):267-268. 
3.    Grajower M, Horne B. Clinical Management of Intermittent Fasting in Patients with Diabetes Mellitus. Nutrients. 2019;11(4):873. 
4.    Fernández-Cardona A, González-Devia D, Mendivil C. Intermittent Fasting as a Trigger of Ketoacidosis in a Patient With Stable, Long-term Type 1 Diabetes. J Endocr Soc. 2020;4(10). 
5.    Al-Ozairi E, El Samad A, Al Kandari J, Aldibbiat A. Intermittent Fasting Could Be Safely Achieved in People With Type 1 Diabetes Undergoing Structured Education and Advanced Glucose Monitoring. Front Endocrinol (Lausanne). 2019;10. 
6.    Cheng C, Villani V, Buono R et al. Fasting-Mimicking Diet Promotes Ngn3-Driven β-Cell Regeneration to Reverse Diabetes. Cell. 2017;168(5):775-788.e12. 
7. Intermittent fasting may not work for everyone, researchers discover. Available at: Published 2020. [Accessed March 2021].