Fasting and Gut Health: What's the Link?

Fasting and Gut Health: What's the Link?

May 24, 2022 5 min read

Fasting and Gut Health: What's the Link?

With the numerous diet and wellness crazes comes intermittent fasting. This type of fasting is a pattern that involves eating for certain periods of time while stopping food intake for others, on a regular schedule. There are numerous types of this eating craze that people believe can be their perfect tool for weight loss and to achieving wellness. This article will overview the benefits of intermittent fasting and its effect on your gut.

Intermittent Fasting and History

When you are eating only during a certain period of time and then stop for the remaining hours within a day, you are following an intermittent fasting. According to researchers from John Hopkins, in prehistoric times, long before people learned how to farm and grow their own crops, they were obliged to stay long periods of time without food. It all depended on the food they were able to gather and hunt. Even when things evolved, like fifty years ago, people used to have smaller portions of food, sleep early and eventually end up having some kind of intermittent fasting (1).

People were slimmer. Now, with industrialization, every one of us is exposed to a lifestyle that may be nuisance to our body. People started going out more often for dinners at restaurants, spending long nights watching movies or surfing the internet and having such a wide variety of heavy food. All these unhealthy habits, not only sabotaged the more primitive healthy eating habits but it also dragged people towards sedentary lives. Now, People want to be healthy and that’s how prehistoric diet types came back to life. People are now, more than ever, believing in intermittent fasting.

Intermittent fasting and your Health

Unlike what the American diet represents, intermittent fasting encourages healthy eating as well as fluid intake during the fasting time. Teas, water and herbal infusions are encouraged during fasting which increases their intake tremendously. In addition to offering healthier options, intermittent fasting can have several health benefits.

When you are fasting, you are keeping your body away from food. After hours without food, your body will eventually use up all your sugar reserves and initiates energy production by breaking down fat. This is referred to as metabolic switching. When you are on a regular eating pattern, your body’s energy needs depend on the food you are eating on a daily basis. When you fast, your body will break what it already has. This process may trigger weight loss.

Fasting normally has three stages: the eating stage, the post-absorptive stage and the fasting stage. During the first stage, you burn glucose that is obtained from carbohydrates and proteins. Your insulin levels are at their highest. This phase spreads over a period of three to five hours. During the second stage, the post-absorptive stage, that lasts for eight to twelves hours post eating the past meal, your body is still digesting what it ate. The third stage, the fasting stage, you begin burning fat to produce energy. Your insulin levels during this stage are low and so is your blood glucose levels. This fasting stage is essential to make the metabolic shift and an easy way to help you lose weight and regulate other functions in your body.

Health benefits of intermittent fasting boosting memory, balancing blood pressure and resting heart rates, boosting endurance, preventing obesity and lowering damages tissues especially for those who underwent surgeries.


Two people sit at a table with no food, overlooking a large body of water


Intermittent fasting and your gut

Intermittent fasting has many effects on your body’s physiology (2). Stimulating autophagy, inhibiting motor pathways and inducing ketosis are not the only health benefits of intermittent fasting.  Studies indicate that fasting can affect your gut.

When numerous studies have linked diet and the effect of food to your gut, why wouldn’t changes in dietary patterns cause a similar effect (3)?

A study published by the Turkish Journal of Gastroenterology explained that fasting increases the abundance of certain types of good bacteria namely Bacteroides fragilis and Akkermansia muciniphila. The researchers explained that fasting did trigger a resistance to dietary changes in gut microbiota (4).

The Massachusetts Institute of Technology explains that as people age, the stem cells in their intestines stop regenerating. This will slow down the production of new cells in the intestines, which makes is tougher to recover from gastrointestinal infections and other illnesses of the lower tract. What these researchers discovered is that such a decline in stem cells renewal can be reversed by adopting fasting. They explained further that upon fasting, fatty acids from cells become the source of energy instead of the regular glucose. This change stimulates stem cells regeneration and aids recovery of damaged intestinal infections (5).

In addition, in order to optimize the benefits of fasting on the gut, studies have found that you would need to couple it with a gut-healthy diet that involves diversity and anti-inflammatory food options (6). There are several factors to keep in mind when aiming at implementing intermittent fasting to your gut’s health.

Fix your Gut Issues

Fixing the problems at the level of your gut is your first step. If you believe that you may some intestinal problems or dysbiosis, you need to heal your gut before beginning your fasting regimen. Remember that it all starts with a happy healthy gut.

Gut Sensitivities

Make sure you do not forget about your food sensitivities that can have a heavy impact on your microbiome. Food that are considered to be offenders to your intestinal lining have to be stopped completely. You cannot be on an intermittent fasting diet that promotes healthy gut when you are bloated and have inflammations caused by certain types of food.

Add fermented food

Fermented food can help regenerate your gut microflora. For those who are not eating regularly fermented food, you can incorporate probiotics that can offer you several billion colonies of Lactobacillus and Bifidobacterium.*

Keto added to your fasting diet

While intermittent fasting triggers the breakdown of fatty acids instead of carbohydrates, having a parallel ketogenic diet can help maximize the effects of your fasting diet. So, try to have food that are high in proteins and high in fiber like plant-based food.


A glass of water sits on a table, with a few green herbs sticking out of it


Consequences of Intermittent fasting

Numerous studies linked intermittent fasting to weigh loss, a healthier body, as well as a better control over chronic conditions. Despite all the health benefits this type of diet offers, it is not for everyone. Children under the age of eighteen, pregnant and breastfeeding women, those who have eating disorders need to stay away from fasting in general, let alone a fasting diet that bans them from eating during prolonged periods of time.

Some people that do not belong to these categories even report certain side effects like experiencing mood swings, low energy, constipation, electrolyte imbalances, extreme cravings, unregulated sleeping patterns, and binge eating.

Some studies looked deeper at the possible side effects of intermittent fasting and came across the gallbladder. This small pear-shaped organ that is located under the liver and produces the bile. This fluid helps promoting the digestion of fatty acids and fats. During the meals, the bile is released into the digestive tract and in between meals, it gets stored in the gallbladder. When you are fasting, you are depriving your system from certain energy forming food. The body begins to break down fat. As a result, your liver will start making more cholesterol pouring it into the bile that is now being kept in the gallbladder for longer periods of time. As a result, gallstones may start forming and enlarging leading to health problems and abdominal pains (6).

In summary, despite the minimal health consequences that one can experience while on intermittent fasting, this type of restricted eating is considered to be a promising non-pharmacological approach to promoting wellness and boosting health through regulating the circadian biology, the gut microbiome, and lifestyle adjustments.


Dr. Sandra El Haaj, contributing writer for Physician's Choice

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