How Does Fasting Affect Gut Health?


You may have heard about intermittent fasting in recent years. In fact, if you keep up with dietary trends it’s probably all you have heard about. There’s a reason why so many experts recommend intermittent fasting to help improve your overall wellbeing. One of those reasons is the positive effect it has on your gut health. This article will go over how intermittent fasting can boost gut health, how it can help with digestive problems, and what risks you should look out for. 

What Are the Gut Benefits of Fasting?

As we develop a better understanding of the health benefits of fasting, we learn more and more about how fasting impacts our gut health. We all know that what you eat impacts your gut health. However, researchers now believe how often you eat and when you eat also have an impact on the wellbeing of your gut. Here are some of the health benefits of fasting and how fasting helps your gut:

  • Give your digestive system a break - Digesting food is an energy-intensive task. Fasting can help decrease postprandial endotoxemia which research suggests increases the risk for obesity and insulin resistance
  • Sync up with your body clock - Just like the rest of our body, our gut microbes operate on a circadian rhythm. Eating late at night can disrupt this rhythm, which decreases tolerance against bad microbes
  • Increased longevity - Research on animals with similar digestive systems as humans - such as fruit flies - has found that fasting can boost longevity due in large part to the role it has on our gut health

As you will learn later in the article, fasting provides numerous benefits, not just increased gut health. While a healthy gut helps improve our overall well being, we still need the rest of our body to be relatively healthy if we want to live a long, healthy, and happy life. 

Can You Start Healing Your Gut With Fasting?

It should be noted that there are no immediate fixes when it comes to improving your gut health. Sure, you can start to feel the effects of improved gut health in only a few days, but it takes long-lasting healthy lifestyle changes to see a permanent change. Here are some of the ways you can utilize fasting to heal gut problems:

  • Check with your doctor first - This may seem like a strange first step, but it’s important to make sure your gut issues aren’t part of a deeper underlying condition that may require further treatment. It’s also important to ensure fasting is something you can do healthily
  • Be mindful of food sensitivities - Eating gluten, soy, and dairy when you are sensitive to these foods can wreak havoc on your gut
  • Eat fermented and cultured foods - Fermented foods work wonders when it comes to the growth and proliferation of your good bacteria
  • Combine fasting with keto - Fasting doesn’t have to be the end-all-be-all of your diet. Pair it with another diet such as the keto diet to amplify your results

Again, your gut health will improve simply by improving your overall health. In order to see long-term results, you need to commit to long-term lifestyle changes that make you healthier. 

Can Fasting Help Digestive Problems?

Remember, there are no quick-fix schemes that improve your gut health immediately. Improvements in your gut health due to fasting come over time. To add to this, fasting can boost your gut health in roundabout ways as well. Here are some of the ways you can use fasting to heal digestive problems:

  • Improved digestion
  • Reduced food cravings
  • Increased mental focus and concentration 
  • More stable energy levels
  • Improved mood
  • Fat loss
  • Decreased inflammation
  • Heart disease prevention

Take reduced food cravings for example; the less you want to eat, the more likely it is that you avoid foods that are bad for your gut. By avoiding these foods, you are implementing long-term healthy lifestyle changes that will provide long-term results. 

Does Intermittent Fasting Help Gut Bacteria?

We must mention the fact that research into gut health and the impact fasting has on our gut is still in its infancy. There is much we need to learn before we can jump to any definitive conclusion one way or the other. With that being said, researchers do waver on whether or not intermittent fasting is good for your overall well-being long-term. 

Many experts who argue against intermittent fasting argue against extreme fasting diets; for example - 24-hour fasts, ‘juice cleanses’, and spartan fasting. Most experts agree that a healthy form of fasting - such as a 16:8 or 12:12 fasting plan - is much more sustainable and contains fewer risks. 

What Are the Risks and Side Effects of Intermittent Fasting?

Some experts are turned off by the idea of fasting because there are some risks involved. As we just mentioned, as long as you aren’t practicing an extreme diet, you should be safe. However, there are some side effects of intermittent fasting that you need to be on the lookout for. Here are some of those effects:

  • Intermittent fasting may make you feel sick - If you begin to feel woozy or lightheaded, you should break your fast and eat something as soon as possible. This is why experts recommend a fasting method that allows you to eat every day within a certain time period
  • It can lead to overeating - Humans have a biological urge to overeat after long periods without food. This is because the appetite hormones and hunger center in your brain go berserk when you are deprived of food.
  • Intermittent fasting can lead to too much weight loss - Intermittent fasting can lead to rapid weight loss, especially in older adults. While weight loss is considered a good thing, too much weight loss can be unhealthy
  • It can be dangerous depending on the medication you take - There’s a reason why experts recommend you consult with your doctor before beginning a fasting diet. That’s because fasting may not combine well with certain medications

Supplements Can Help

One supplement that can help encourage positive gut health is spermidine. This is because spermidine helps induce something called autophagy. This is the body’s process of replacing old and potentially damaged cell parts with newer, healthier ones. Autophagy literally means ‘self-eat.’

This process helps keep you feeling and looking young while also dramatically lowering your chances of developing aging diseases such as Parkinson’s and Alzheimer’s. While it is possible to get your recommended daily intake of spermidine through your diet, it’s recommended to take supplements so you ensure you get the right dose. Simply taking your supplements with your dinner is a great way to remember to take spermidine supplements every night.


  • Don Moxley - Director of Applied Science

    Don Moxley is the Director of Applied Science at Longevity Labs. Moxley draws upon his career as an athlete, a sports scientist, and an instructor to lead and educate on the science of autophagy and longevity.