Many clients come to us with digestive issues like SIBO and IBS. They have gas, bloating, constipation, diarrhea and/or acid reflux. They start restricting more and more food and before they know it, they are eating a very limited diet.
There are many different types of fasting. What they may not realize is that with gut health, WHEN you eat is as important as what you eat. Giving your stomach some time to digest food in the form of a short fast may improve gut health…which can help you feel better and help you broaden your diet.
What are the different types of fasting that can potentially offer gut health healing potential?
Sometimes the best solutions are actually not all that complicated…and you might be fasting more than you’d guess right now.
In this article, we’ll be going over the different types of fasting and what potential benefits they offer. We’ll also cover how to get started with fasting if you’d like to give it a try as well as who should not be trying fasting.
Let’s dive in!
Simple fasting
You might already be practicing simple fasts, actually.
Let me ask you one question: do you snack or nibble or graze between meals? Do you have a bowl of crunchy snacks next to your computer keyboard or cut-up fruit that you munch on all day?
Or, do you just stick to eating at mealtimes and only have water, plain tea or coffee between meals?
If you don’t usually eat or drink anything between meals, you are already having simple fasts.
There are benefits to this practice: your gut thrives with the chance to digest meals, without the addition of new foods. Simple fasting could be spacing your meals 3 – 5 hours apart. This simple fasting helps improve the migrating motor complex of the small intestine.
The migrating motor complex (MMC) is a complex movement cycle of the GI tract – basically, moving food along the tract so that we can fully digest and absorb nutrients. What pumps the brakes? Eating! The MMC is interrupted by eating or drinking anything with calories (1).
(Psst… did you know that MMC dysfunction is a risk factor for recurring SIBO (2)?)
We often recommend meal spacing for those with SIBO in order to improve the function of the MMC and to help optimize digestive function. When I had SIBO, I used to have small, frequent meals and snacks. After implementing a 4 hour fast between meals, I noticed much improvement with my SIBO symptoms. Even though I no longer struggle with SIBO, I still practice meal spacing as well as a 12-hour fast (more on that below). These simple changes have really helped tremendously improve my gut health!
12-hour fasting
Do you know that your gut is in need of daily repairs? The work of digestion and absorption is tough on your gut. As such, it needs regular time to repair itself. The most important time this happens is at night when you’re sleeping…one more reason that a good night’s sleep is so important!
Digestion slows down at night. This is why late-night eating can often lead to acid reflux and morning diarrhea. A 12-hour fast between dinner and breakfast can help the digestive tract by giving it a well-deserved break. A break from digestion gives the gut time to do its normal repair work.
For more on sleep, check out our blog post: Is Poor Sleep Causing Your Digestive Symptoms?
SIBO & Acid Reflux Case Study
Our client Samantha suffered from SIBO and acid reflux. After reviewing her food journals, we noticed she was eating snacks or sweets after 9pm. She would feel bloated soon after and wake in the morning with acid reflux.
One of the first changes we made, was to ensure that she had her last bite of food with dinner no later than 7pm. Within a few days, her late-night bloating improved and her morning acid reflux became much less frequent.
Want to try 12-hour fasting? Instead of having snacks late into the evening, keep 12 hours food-free between your dinner and breakfast. This is a simple fast.
Intermittent fasting
Intermittent fasting is the most structured fasting that we’ll cover in this article. It’s been receiving a lot of attention for weight loss, longevity and gut health. Basically, in this form of fasting, you extend the period of fasting past 12 hours. Common fasting periods range anywhere from 14 to 16 hours. That means you are only eating food in a 8 – 10 hour window.
There are lots of things to consider before trying this so I want to share what we see in our practice with our clients who try it for weight loss and gut health.
- Most clients feel awful doing intermittent fasting because they are hungry, anxious, it can cause headaches, fatigue, etc and many folks focus on the rules of eating between this time and that time, instead of listening to their body.
- This causes stress and stress makes GI symptoms worse.
- If you are trying to get a full day’s worth of food into a very short window like 8 hours, that means having bigger meals and for many people with GI issues like SIBO, IBS and reflux… bigger meals can make you feel worse.
In short, we RARELY recommend intermittent fasting and have our clients focus on meal spacing and a more gentle fast between dinner and breakfast.
No matter which form of fasting you choose, we do not recommend skipping breakfast. Have breakfast, with a good amount of protein, to optimize your energy and digestion. For more on protein, check out: How Much Protein Do You Need & When Should You Eat It?
If you’re looking for something to enjoy in the evening once your “eating window” has closed, you might consider tea! There are several teas that can further support symptom management and we cover them here: Teas for Digestive Distress: Bloating, Gas, Nausea, Reflux & More.
Let’s cover a bit more of the details for how fasting might improve digestion.
Potential benefits for different types of fasting
There are many proposed and potential benefits of fasting. For this article, we’re focusing on the benefits related to gut health and digestion.
Research on various fasting regimens is underway. Much of the research is done in animals first, which shows promising results, but keep in mind that we are not fruit flies or mice, as are some of the test subjects. The more we are able to do research in humans, the better we’ll understand the potential benefits of fasting.
Improved gut permeability
Have you heard of leaky gut? This is the condition in which food fragments, bacteria and other compounds can sneak through the gut lining, causing food sensitivities and inflammation in the body. In normal, healthy digestion and absorption, the gut lining is quite selective about what is absorbed.
Your gut permeability is dynamic; many factors influence its permeability including the microbiome, genetics, and other lifestyle factors such as usual diet and how well you sleep.
Fasting may improve gut permeability, making your gut less “leaky” (3).
Improving the microbiome
We learn more every day about how much the microbiome – the community of good bacteria and other organisms in our gut – can impact our health overall. Dysfunction in the microbiome can cause disease whereas a balanced and vibrant microbiome can improve health and quell symptoms.
Overall, intermittent fasting can positively impact the microbiome and improve health (4).
Inflammation
Inflammation is a natural and normal body response to an infection or injury; your skin swells and warms up, making it easier for your immune system to fight the bad bacteria as well as heal the cut (5).
Chronic inflammation – this reaction happening for an extended period – is the common denominator for many chronic diseases, including diabetes and heart disease. There is evidence that intermittent fasting may reduce markers of inflammation, lowering the risk of chronic disease (6).
Aging
Animal studies have found that intermittent fasting may slow aging, by improving gut health (7). Fasting may improve neural function as well, another pathway to healthy aging (8).
Who should avoid fasting?
It’s important to note that simply not eating, or not having access to food, comes with risks. As noted above, not eating when hungry or in need of energy, may cause fatigue, create a stress response in the body (which can exacerbate gut symptoms) and it can depress the immune system. Keep in mind that the various forms of fasting discussed here are alternating patterns of eating and fasting, not simply avoiding eating.
We often have clients come to us following a restrictive diet, taking a gazillion supplements and practicing extreme fasts of 14 – 16 hours. Their doctor may have recommended intermittent fasting or they may have read about how fasting can improve gut health. But what they don’t realize is that not everyone is a great candidate for fasting. They often feel worse because fasting exacerbates existing health issues.
Who should avoid fasting?
History of disordered eating
For people with current or past disordered eating, embarking on any kind of fasting may be triggering to their condition. For some, having a new diagnosis of a different condition, such as IBS, can be a trigger to return to disordered eating patterns (9). We do not recommend fasting if you have a history of disordered eating.
Hypoglycemia
Are you the person who goes from friendly to cranky if they miss their afternoon snack? Or do you get headaches or feel shaky if you miss a meal because of a crazy day? This may mean that you’re prone to low blood sugar, aka, hypoglycemia. Fasting may not be a good fit for you, either (10).
Hypothyroidism
If you have hypothyroidism, the data on how fasting might affect your condition is mixed. For some people with hypothyroidism, fasting may cause a drop in blood sugar.
We can study the effects of fasting among those who observe Ramadan. In one study, participants had higher TSH values (which means reduced thyroid function) after Ramadan concluded (11).
If you have a thyroid condition, please speak with your doctor before making changes to your diet.
Gastroparesis
For anyone with gastroparesis – delayed gastric emptying – fasting is not a great fit. For this condition, people feel best with small frequent meals, as opposed to fasting.
Underweight
For anyone who is underweight, or having a hard time maintaining a healthy weight, we do not recommend fasting.
How to get started with fasting?
The best way to get started with fasting is to begin slowly. We recommend starting with the simplest form of fasting – less snacking between meals and see if you notice improvements in your digestion, energy or focus.
If you find that fasting is helping you to feel better, without any low-blood sugar symptoms, you’re welcome to work towards the 12-hour fasting between dinner and breakfast. And remember, we don’t recommend skipping breakfast.
Key takeaways: Different types of fasting
So many different factors influence your digestion and how you feel. We tend to think about what we’re eating first, which is a big piece of the puzzle. But in this article, we have covered how meal timing and fasting is another factor, too.
If you’ve been struggling with unrelenting digestive symptoms, we’d love to help you feel better. Use this calendar to book a Free 15-Minute Strategy Session to learn more about our approach to your case.
Sara Kahn, MS, CNS, CDN is a board-certified nutritionist specializing in digestive health conditions like SIBO, IBS, acid reflux and more. She’s the founder of Belly Bliss Nutrition and the Solving SIBO Program.
