If you have type 1 diabetes, you likely already know that diabetes management involves careful attention to diet and exercise, because they both affect your blood glucose (blood sugar) levels. Though trying one of the latest type 1 diabetes diet trends — such as an intermittent fasting diet — is tempting, understanding how dietary changes may affect your condition is essential. The best place to start is having a conversation with your health care professional.

Read on to learn some of the important facts about intermittent fasting, including potential benefits and other ways it may impact type 1 diabetes.

What Is Intermittent Fasting?

Intermittent fasting isn’t a diet in the traditional sense of the word as it focuses on when you eat rather than what you eat. Essentially, it’s a time-restricted eating plan. Proponents of intermittent fasting argue that early humans, as hunter-gatherers, were accustomed to eating when food was available, which meant they often had to fast. As a result, their bodies adapted to store nutrients to survive when they couldn’t hunt.

Fasting is not a new concept; it has been around for thousands of years and remains common in many cultural and religious practices around the world. During Ramadan, for example, Muslims fast from dawn until sunset for up to 30 consecutive days.

Some health benefits of following an intermittent-fasting eating pattern include:

• Potential weight loss
• Improved blood glucose levels and cardiovascular markers
• Reduced inflammation
• Better insulin sensitivity (how well our cells use insulin and blood sugar)

However, it's crucial to consult your doctor before starting intermittent fasting, as it can reduce the effectiveness of your diabetes medication and cause fluctuations in your insulin levels.

Types of Intermittent Fasting

There are a few versions of intermittent fasting periods. One version, the 16/8 method, allows you to eat normally for eight hours, followed by 16 hours of fasting. During the fasting time, you can drink water or other calorie-free fluids but may not have any food. Practically speaking, if you choose this method and sleep eight hours a night, you’re going without food for only eight waking hours.

The 5:2 approach, also referred to as “alternate day fasting,” lets you eat normally five days of the week. On the other two days (whichever days you choose), you only consume one meal with a maximum of 500 to 600 calories. The rest of the day, you fast.

It’s important to remember that if you fast for too long (for instance, beyond 24, 48, or 72 hours), your body might shift into survival mode, which may make it much harder to lose weight and derive the other benefits of intermittent fasting. But it all depends on your body and what works best for you.

Intermittent Fasting Among People With Type 1 Diabetes

Research on intermittent fasting for people with type 1 diabetes is limited, and the results of existing studies have been mixed. One study found that fasting may lower the risk of developing hypoglycemia (low blood sugar) among those with type 1 diabetes while improving fat metabolism, boosting insulin sensitivity, and improving body composition (achieving a healthy balance between fat and lean muscle).

Another study noted that following an intermittent-fasting eating plan could improve glycemic control (stabilize blood glucose levels), reduce body weight, and improve hemoglobin A1C levels (measure of average blood sugar levels over time) among individuals with type 1 diabetes.

However, it’s important to remember that people with type 1 diabetes must also maintain a balance of healthy behaviors to function well. That balance includes:

• Eating the right kinds of food
• Achieving a certain level of exercise
• Finding the right dosage of insulin
• Getting plenty of restorative sleep

Anything that upsets that balance while fasting can have undesirable consequences in terms of blood sugar levels and glycemic control.

In addition, some experts caution that following an intermittent-fasting eating plan may reduce blood glucose levels to a dangerously low point during fasting periods. Uncontrolled fasting can also lead to kidney damage and diabetic ketoacidosis (potentially dangerous buildup of acid in the blood) among people with type 1 diabetes.

Always talk to your doctor before changing your eating plan. If your health care practitioner gives you the go-ahead to try intermittent fasting, they will likely adjust your insulin intake. For instance, they may ask you to stop taking doses of fast-acting insulin or cut down on the basal insulin dose you take to accommodate for the changes you’ll likely experience in insulin sensitivity.

They may also recommend using a continuous glucose monitor (CGM) so you can evaluate your blood sugar levels in real time during your periods of fasting.

Is Intermittent Fasting Safe for Kids With Type 1 Diabetes?

Because children have a greater need for nutrition that allows them to fuel their growing bodies, intermittent fasting isn’t typically recommended for people under 18, especially those with type 1 diabetes.

In addition, it can be hard to plan for how much energy children and young adults will expend each day because of their shifting activities and schedules. As a result, it’s very difficult to gauge whether they’d be taking in the right combination of nutrients if they followed a fasting diet. Any change in the ratio of carbohydrates to other dietary nutrients, as well as calorie intake, could alter their insulin levels in a dangerous way.

Talk to Your Doctor About Intermittent Fasting Before Trying It

If you have type 1 diabetes, it’s essential to speak with your endocrinology care team or another health care provider before changing your eating habits. They can help you determine the safest and most effective ways to calculate your nutritional needs and activity goals while maintaining a healthy blood glucose level. They can also discuss the potential positive and negative effects of intermittent fasting or other calorie restriction plans and whether they may be right for you.

If you’re interested in changing how you eat with type 1 diabetes, your endocrinologist may put you in touch with a registered dietitian, who can help you develop an eating plan that’s tailored to your condition.

Find Your Team

On myT1Dteam, the social network for people with type 1 diabetes and their loved ones, more than 3,500 members come together to ask questions, give advice, and share their stories with others who understand life with type 1 diabetes.

Have you ever tried intermittent fasting while living with type 1 diabetes? Share your experiences in the comments below, or start a conversation by posting on your Activities page.