Fasting has been found to promote the growth and production of essential nutrients by the trillions of microorganisms residing in your gut.

Your intestines play host to numerous microorganisms that aid in the breakdown of food and the production of nutrients, such as B vitamins and vitamin K. By promoting the growth of these microorganisms, fasting can be a beneficial approach to enhance overall gut health. There are several fasting techniques that can be tailored to individual preferences and lifestyles, all of which have the potential to improve your gut health. If you want to learn more about fasting and its potential benefits for your gut, explore further resources on the topic.

The Benefits of a Healthy Gut

Let’s discuss why having a healthy gut is crucial. When microorganisms in your gut digest dietary fiber, they create compounds that play a critical role in muscle function and disease prevention. Surprisingly, these gut bugs also influence emotions and cognition by communicating signals between the brain and digestive system.

As per Suzanne Devkota, PhD, director of microbiome research at the F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute at Cedars-Sinai in Los Angeles, “We really rely on them and need them. They play a fundamental nutritional role for us.”

Maintaining a healthy balance between good and bad bugs by feeding them the right food can give you significant health benefits. Having a healthy balance of microbes in your gut lowers the risk of developing chronic conditions, including heart disease, diabetes, asthma, chronic kidney disease, rheumatoid arthritis, irritable bowel syndrome, and mental health conditions.

Interestingly, it’s not just the type of food you consume that impacts the balance of microorganisms in your gut, but also the timing of your meals (and perhaps more significantly, the timing of your fasts). Research indicates that when you eat has a significant impact on your microbiome.

Use Intermittent Fasting

Incorporating intermittent fasting into your routine can be achieved in various ways. Two popular approaches are time-restricted feeding and weekly intermittent fasting. Time-restricted feeding involves limiting your daily eating period to a specific number of hours, while fasting for the remaining time. Weekly intermittent fasting entails restricting food intake on two to three nonconsecutive days per week.

Studies suggest that both methods can result in weight loss and improved metabolic function, ultimately reducing the risk of diabetes and cancer. However, most of these studies have been conducted on rodents, and the few human studies conducted have produced mixed results. Further research is needed to determine the effectiveness of these fasting techniques.

It’s essential to note that pregnant or breastfeeding individuals and those with a history of disordered eating should avoid any form of fasting.

Changing Gut Microbiome

Devkota explains that intermittent fasting can have an impact on the composition of your gut microbiome. “Your gut bacteria are highly responsive to the presence or absence of food,” she says. “When you remove food, the microbiome’s composition shifts.”

One particular bacteria, Akkermansia muciniphila, rapidly expands and is linked to positive health indicators such as a healthier gut barrier and decreased intestinal inflammation. The gut barrier is the lining of the intestines, which permits nutrients to pass through while blocking bacteria and other harmful microorganisms.

According to Amir Zarrinpar, an assistant professor of gastroenterology at the University of California San Diego School of Medicine, animal studies suggest that the microbiome has its own circadian rhythm, cycling between different populations. Dr. Zarrinpar suggests that when humans are sleeping and not eating, one set of bacteria may thrive. When we wake up and start eating, other bacteria may take over. This cycle repeats every 24 hours but can be disrupted by eating off-schedule or consuming an unhealthy diet. Time-restricted feeding can help restore and reinforce these natural fluctuations, according to a study co-authored by Dr. Zarrinpar and published in Trends in Endocrinology & Metabolism.

Types of Fasting

There are several intermittent fasting patterns, but two common types are:

• 16:8 time-restricted feeding, where you fast for 16 hours and eat during the remaining eight hours.
• 5:2 weekly fasting, where you eat normally for five days of the week and severely restrict food calories for two nonconsecutive days of the week.

5:2 Fasting

Intermittent fasting has different patterns, and one common type is the 5:2 plan. According to Devkota, this plan has its own advantages and disadvantages. In studies conducted with mice, Devkota found that beneficial bacteria start to increase after 16 to 18 hours of fasting. However, for humans, it may take longer to see the same effect.

Devkota suggested that if one wants to see changes at the cellular or microbiome level, they need to push the fasting period longer. Although the fasting days don’t have to be completely calorie-free, Devkota recommends reducing calorie intake on fasting days by 70% to 75%. However, even reducing calorie intake by 60% can make a difference.

It’s essential to remember that results from animal studies may not necessarily translate to humans. Therefore, more research is needed to confirm the positive changes in gut bacteria that occur due to fasting in humans.

16:8 Fasting

Experts recommend different intermittent fasting patterns. One common type is the 16:8 protocol, where you prolong your overnight fast each day by eating breakfast slightly later and finishing your last meal in the early evening, so your eating window is just eight hours. Even a less intense version of the 16:8 protocol shows beneficial health effects, according to Dorothy Sears, PhD, a professor of medicine at the University of California San Diego School of Medicine.

Sears suggests 12 to 14 hours of fasting overnight, with your eating window ending between 5 and 8 p.m. During your eating periods, it’s essential not to restrict your calorie intake. Most of your gut bugs need food to survive, and you also need food for energy and other functions. “When your body enters starvation mode, like if you fast for too long, you’ll decrease the diversity of bacteria in your gut,” warned Devkota. He recommended ensuring that your fasting is “truly intermittent” and that you don’t fast for two days in a row.

Eating by the Clock

Following a fasting routine on a 24-hour cycle, such as a 16:8 or 14:10 breakdown, allows you to sync your fasting with your natural sleep/wake cycles. This is important because nutrient processing is regulated by circadian rhythms, according to Sears.

Insulin, for example, is most effective in the morning and midday, and insulin secretion decreases in the evening and overnight, as explained by Sears. “If you eat a snack at night, the insulin you secrete to process it isn’t going to function as well as if you ate that same food for breakfast,” said Sears.

When insulin response is dampened in the evening, your blood sugar stays higher for longer, which can increase your risk for cardiovascular disease, type 2 diabetes, and stroke, explained Sears.

To align your food intake with your circadian rhythm and still achieve a prolonged overnight fast, try eating breakfast a little later (around 8 or 9 a.m.) and finishing dinner a bit earlier (around 6 p.m.). This can help regulate your nutrient processing and reduce the risk of health issues.

A Quick Review

A healthy gut has been linked to a range of health benefits and can help prevent chronic conditions. Intermittent fasting is one approach that can be used to improve gut health, and it can take various forms, such as weekly day fasting or daily hour-based fasting. With a variety of fasting schedules available, it’s possible to find one that fits your preferences and schedule to promote overall health. However, before starting any fasting regimen, it’s important to consult with a healthcare provider to determine the best approach for you.

FAQs about Fasting for Gut Health

1. How long should you do fasting?

The duration of fasting can vary depending on the type of fast and individual goals. Some people opt for short fasts, such as intermittent fasting for 16 hours each day, while others may fast for several days or even weeks. It’s important to consult with a healthcare provider before starting any extended fasting program.

1. Is fasting good for the body?

Fasting can be beneficial for the body in a number of ways. It can improve gut health, reduce inflammation, boost immunity, promote weight loss, and improve metabolic health. However, it’s important to practice safe and healthy fasting habits and listen to your body’s needs.

1. What are the 3 types of fasting?

There are several types of fasting, including:

• Intermittent fasting: This involves alternating periods of eating and fasting, such as the 16/8 method or the 5:2 method.
• Water fasting: This involves abstaining from all food and drink except water for a period of time.
• Juice fasting: This involves consuming only fruit and vegetable juices for a period of time.
• Other types of fasting include partial fasting, where certain foods or food groups are eliminated for a period of time, and religious fasting, which is practiced for spiritual reasons.

1. What do you eat when fasting?

During a fast, food is generally avoided. However, it’s important to stay hydrated and nourished by drinking plenty of water and consuming nutrient-dense beverages such as herbal tea or bone broth. Some people also choose to consume small amounts of healthy fats, such as coconut oil or avocado, to help with satiety and provide energy. It’s important to consult with a healthcare provider before starting any fasting program and to listen to your body’s needs.

Discover more articles about Fasting:

What Is Intermittent Fasting?

Is Intermittent Fasting Bad for You?