Key Takeaways
- Intermittent fasting is a diet that alternates between set periods of fasting and unrestricted eating. There are many different variations, including time-restricted feeding and alternate-day fasting.
- Research shows that intermittent fasting may benefit people with prediabetes by reducing blood sugar levels and improving insulin resistance, though more studies are needed.
- Talk to your doctor before starting an intermittent fasting plan. Begin with the least restrictive version of the plan, stay hydrated, and listen to your body.
If you have prediabetes, you may be wondering if intermittent fasting (IF) could be a good fit for you.
Intermittent fasting is a popular diet trend with emerging research on its possible metabolic and health benefits.
Though research is still in the early stages, many people choose to try IF in an attempt to lose weight and improve their metabolism.
Continue reading to learn more about how IF works and the best intermittent fasting plans for prediabetes.
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What Is Intermittent Fasting?
Intermittent fasting (IF) is an eating pattern that involves alternating between periods of fasting and unrestricted eating.
It’s a popular alternative to daily calorie restriction, in which a person follows a low-calorie diet every day.
While intermittent fasting is most commonly used as a weight management strategy, it’s also been studied in the context of diabetes, heart disease, and metabolic syndrome.
How Does it Help Prediabetes?
Because some studies show there are health benefits of intermittent fasting, researchers are studying how it may help manage prediabetes.
Prediabetes is a condition in which blood sugar levels are higher than normal but not high enough to be considered diabetes.
People with prediabetes have an increased risk of developing type 2 diabetes, but diet and lifestyle changes may prevent this.
Benefits
Preliminary research shows that intermittent fasting may improve insulin resistance, lower blood sugar levels, and reduce cardiovascular risk in people with prediabetes.
As a result, IF may benefit a person’s metabolism while assisting with weight management, which can help prevent type 2 diabetes.
However, long-term research on intermittent fasting and prediabetes is limited.
More high-quality studies are needed so doctors can make recommendations on safely following IF diets in this population.
Risks
Because people with prediabetes are more prone to experiencing abnormal blood sugar fluctuations, it’s important to talk with your doctor about your risk of hypoglycemia (low blood sugar levels) that may occur with certain types of intermittent fasting.
Similarly, you may experience high blood sugar levels if your daily eating window is very small, meaning you’re eating all of your calories within a short period rather than spaced out throughout the day.
However, these risks are more common in people with type 2 diabetes.
Prediabetes is generally considered a low-risk population for intermittent fasting complications.
Other Considerations
There’s also a risk of dehydration with intermittent fasting, especially on fasting days and when you’re very active.
Additionally, intermittent fasting may contribute to disordered eating because it encourages ignoring your natural hunger and fullness cues by restricting your daily eating window or fasting on specific days.
As with any restrictive diet, weight regain may occur once you stop intermittent fasting.
Intermittent fasting isn’t recommended for people with:
- A history of hypoglycemia (low blood sugar reactions).
- Current pregnancy or breastfeeding status.
- Advanced age.
- Eating disorders.
- Immunodeficiencies.
Types of Intermittent Fasting
There are many different types of intermittent fasting, most of which involve at least one of the following methods:
- Very low or no calorie intake on specific days of the week.
- Restrictions on the times of day a person can eat.
Some methods are much more restrictive than others, which may increase the risks (such as hypoglycemia, dehydration, and disordered eating) and be more challenging to sustain over time.
The following descriptions are for educational purposes. Nourish does not recommend following highly restrictive diets.
Time-Restricted Feeding
Also known as the 16/8 method, time-restricted feeding usually involves an eating window of eight hours during the day followed by a fasting period of 16 hours overnight.
For example, a person may eat their meals between the hours of 10 AM and 6 PM daily and then fast from 6 PM until 10 AM the following day.
Time-restricted feeding is the least restrictive method of intermittent fasting and may work well for people who naturally have a low appetite in the mornings.
A small study from 2018 found that after five weeks of time-restricted feeding, participants with prediabetes had better insulin sensitivity, lower insulin levels, and improved blood pressure.
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5:2 Diet
The 5:2 diet is a form of periodic fasting that involves a very low-calorie diet on two non-consecutive days each week.
The remaining five days don’t have any calorie restrictions.
Someone l following this method might restrict their food intake to 500-600 calories per day on Mondays and Thursdays.
Then, they would eat normally for the rest of the days—being mindful of making balanced food choices but not limiting calories.
A 2018 study compared a 5:2 fasting diet with daily calorie restriction in people with type 2 diabetes.
After 12 months, the participants in both groups experienced similar improvements in average blood sugar levels, but the 5:2 group had a greater weight loss result.
Alternate-Day Fasting
Alternate-day fasting is when a person fasts for 24 hours at a time, completing a fast every other day.
For example, a person might fast all day and night on Monday, eat normally on Tuesday (no restrictions), fast on Wednesday, eat normally on Thursday, and so on.
There are different variations of alternate-day fasting.
Some versions of this plan involve consuming zero calories during a fast, while others allow up to 25% of your daily calories each fasting day.
A small study from 2019 compared the effects of alternate-day fasting with continuous calorie restriction on people with metabolic syndrome.
The alternate-day fasting group experienced greater improvements in fasting blood sugar levels, body weight, and blood pressure.
How to Safely Practice Intermittent Fasting
The best intermittent fasting plan for you will be the one that feels realistic and sustainable for your lifestyle and is approved by your doctor or dietitian based on your medical history.
Consider the following tips for prioritizing your health and safety when starting an intermittent fasting plan.
Start Slowly
It can be helpful to begin with a modified version of intermittent fasting in order to find the best plan for you while assessing any risks.
If you’re interested in time-restricted feeding, you can start by slowly lengthening your overnight fasting window from 10 hours to 12 hours and, eventually, 16 hours.
This method will help you find the least restrictive option that is effective for you.
For example, you may find that a 12-hour fast overnight is more realistic than a 16-hour fast.
Additionally, if you experience concerns regarding blood sugar, appetite, or energy levels, you can bring these up with your healthcare provider before moving forward.
Stay Hydrated
Intermittent fasting can make it more challenging to stay adequately hydrated because you may restrict calorie-containing beverages and foods with high water content (kombucha, yogurt, soups, fruits, etc.)
Make hydration a priority, especially during fasting days, to decrease the risk of a blood sugar spike.
Consider your activity level when determining hydration needs, and avoid high-intensity exercise (especially during warm weather) during a fast.
Listen to Your Body
Most importantly, listen to your body as you begin intermittent fasting.
If you experience any concerning symptoms (listed below), discontinue the plan and discuss other options with your healthcare provider.
Concerning symptoms may include:
- Intense hunger.
- Irritability.
- Lightheadedness.
- Fatigue or low energy.
- Low blood sugar levels.
Consider a less restrictive option if the plan doesn’t feel realistic or sustainable.
Remember, the most effective eating pattern is the one you can maintain long-term.
Meal Planning Tips for Intermittent Fasting with Prediabetes
Though most intermittent fasting plans don’t focus on the types of foods you eat, the balance of your meals and snacks is a key part of managing prediabetes.
In addition, some of the more restrictive intermittent fasting plans may make it harder to get all of the nutrients you need, including vitamins, minerals, and protein.
This makes it especially important to prioritize balanced eating.
The diabetes plate method can be a helpful tool for planning nutritionally balanced meals. Focus on including:
- ¼ plate lean proteins.
- ¼ plate high-fiber carbohydrates.
- ½ plate non-starchy vegetables.
- Healthy fats as a condiment or to cook your food.
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Takeaway
Intermittent fasting (IF) involves switching between set periods of fasting and unrestricted eating.
There are many variations of IF, some of which can be highly restrictive.
Research shows that intermittent fasting may help manage prediabetes by improving insulin resistance and lowering blood sugar levels, but more high-quality and long-term studies are needed.
If you’re interested in intermittent fasting, talk to your doctor beforehand and start with the least restrictive plan.
Listen to your body and prioritize hydration and balanced meals.
How a Dietitian Can Help
With so many different intermittent fasting plans available, choosing the best plan for you can feel overwhelming.
A registered dietitian can help you determine whether intermittent fasting is a good fit for you and, if so, how to implement a safe and sustainable plan.
Find a registered dietitian specializing in prediabetes to prioritize your health and feel your best.
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Frequently Asked Questions
Some research shows intermittent fasting can help prediabetes by improving insulin resistance, lowering blood sugar levels, and reducing body weight.
However, more long-term studies are needed to better understand this connection.
It’s generally considered safe to practice intermittent fasting if you have prediabetes.
Talk to your doctor before making any major dietary changes.
Start with the least restrictive IF plan and listen to your body, stopping if it doesn’t feel right.
Since people with prediabetes and type 2 diabetes are at risk of abnormal blood sugar fluctuations, it’s best to avoid long periods of fasting.
If you’re interested in intermittent fasting, consider time-restricted feeding, which typically involves a 16-hour fast overnight with an 8-hour eating window during the day.
As always, talk with your doctor before making any major dietary changes.
The best way to manage type 2 diabetes is with a combination of medication, diet, and lifestyle changes.
Focus on staying active and balancing your plate with lean proteins, high-fiber carbohydrates, non-starchy vegetables, and healthy fats.
Work with your doctor to determine the best medication options and prioritize regular follow-ups.