The microbiome consists of bacteria, archaea, viruses and eukaryotic microbes that live in and on our bodies. A healthy adult will house around different species of bacteria, the majority of which are in the gut. In most people, the core microbiota remain stable throughout adulthood, but the gut microbiota differs between different people.

It is affected by body mass index BMI level, exercise frequency, lifestyle, cultural and dietary habits, and antibiotic use. Studies in people with obesity have found that they tend to have a less diverse gut microbiome , and the balance of species is different from that of leaner people.

Other studies have suggested that the ease with which people lose weight on diets is linked to the composition of their gut microbiome. However, research has not yet revealed a consistent association between gut microbiota and obesity.

A meta-analysis of studies found that weight loss was associated with an increase in microbiome diversity and a reduction in intestinal permeability. Now, a small study from China has suggested that intermittent energy restriction IER , as well as helping people with obesity to lose weight, may alter their gut microbiota.

The study is published in Frontiers in Cellular and Infection Microbiology. None of the participants had any other uncontrolled health conditions. To start, they ate a regular diet for four days, and the researchers recorded the energy content of this as their baseline daily intake.

For the rest of the study, the researchers interspersed the days of regular baseline energy intake with days where the participants had severely restricted energy intake formulated by a clinical dietitian.

They also recorded their body weight , waist circumference, body fat , systolic blood pressure, and diastolic blood pressure at each time point. During the study, participants lost, on average, 7. And at the end of phase II, their gut microbial diversity had increased from the baseline.

However, at the end of phase III, there was no significant difference from the start of the study. There were also some changes in the species making up the gut microbiota, with a decrease in Escherichia coli and an increase in Faecalibacterium prausnitzii, Parabacteroides distasonis, and Bacteroides uniforms.

Kelsey Costa , a registered dietitian and nutrition consultant for the National Coalition on Healthcare, who was not involved in the study, explained how these changes in gut bacteria might affect health:.

prausnitzii is one of the most abundant bacteria in the gut and is generally associated with good health and immunity. distasonis is associated with breaking down carbohydrates and producing useful metabolites.

This bacteria is known to thrive in a diet rich in fiber. uniformis is known to have anti-inflammatory properties and plays a role in processing complex sugars in our diet.

However, it is clear that they are influential actors in our health. Gastroenterologist Dr. It mediates any type of inflammatory process going on within your body.

Inflammation in the body has been implicated in many medical issues, from cancer to diabetes , dementia , and heart disease. In addition, the microbes in the microbiome influence other processes as well, including appetite and obesity. You want a very diverse microbiome in order to decrease and regulate all the mechanisms within your body.

Research bears out the value of a diverse microbiome. The researchers, following their earlier analysis , had commented that the mechanism could be the benefits seen with changes in metabolism, weight loss, cardiometabolic factors, or even improvements in dietary patterns associated with the two arms of intervention.

Bedford suggested a simpler reason. The dietitian also expressed concern that fasting diets and calorie reduction could cause further harm to people with a history of disordered eating.

Fasting can be performed in a variety of ways. While participants in the study fasted 3 days a week, fasting can also be done for a few hours, or for multiple days in a row.

He cautioned that fasting is not a good idea for people with diabetes, since the prolonged lack of food causes fluctuations of blood sugar and insulin levels. Previous research has found that calorie reduction, if it is too extreme, can cause an increase in pathogenic bacteria in the gut, and may otherwise disrupt the microbiome.

Bedford did not question the findings of this research. However, he suggested that extreme calorie reduction is an unlikely practice.

It takes an enormous amount of discipline to do that. And in terms of plants, again, a very limited number of plant products that we also consume. He noted the existence of so-called blue zones , regions around the world in which people live exceptionally long lives. And it changes the microbiome for the better, and therefore the less disease, fewer issues, and fewer problems.

There is a lot of hype around intermittent fasting, but what are its actual benefits, and what are its limitations? We lay bare the myths and the…. Butyrate sends anti-inflammatory signals to the immune system, which could help reduce pain and other symptoms of gut dysfunction.

Butyrate also improves the barrier function of the intestines, Peppelenbosch says. This is, potentially, a very big deal. If intermittent fasting can turn down inflammation and also help normalize the walls of the GI tract, those changes may have major therapeutic implications.

Lachnospiraceae is only one of several types of helpful bacteria that research has linked to fasting plans. But at this point, there are still a lot of gaps in the science. The migrating motor complex refers to recurrent cycles of powerful contractions that sweep the contents of the gut, including its bacteria, down into the colon.

Essentially, this motor complex behaves like a street-cleaning crew tidying up after a parade. It ensures the gut is cleared out and cleaned up in between meals, via minute repeating cycles that fasting allows to be become more frequent. Ideally, Mayer says people could for the most part adhere to the kind of time-restricted eating program that allows a full to hours each day for the motor complex to work.

In other words, sticking to three meals a day and avoiding between-meal bites or nighttime snacks could be sufficient.

Read More: The Truth About Fasting and Type 2 Diabetes. Some researchers have called it a helpful housekeeping mechanism, and it occurs naturally when the body goes without energy calories for an extended period of time. But these improvements have not yet been demonstrated in real-world clinical trials involving people.

Eran Elinav, principal investigator of the Host-Microbiome Interaction Research Group at the Weizmann Institute of Science in Israel. This is likely to have health implications, though what those are, precisely, remains murky.

Read More: What We Know About Leaky Gut Syndrome.

Ganson KT, Rodgers RF, Murray SB, Nagata JM. Prevalence and demographic, substance use, and mental health correlates of fasting among U. college students.

J Eat Disord. Mohr AE, Gumpricht E, Sears DD, Sweazea KL. Recent advances and health implications of dietary fasting regimens on the gut microbiome. Am J Physiol Gastrointest Liver Physiol. Ouyang J, Lin J, Isnard S, et al.

The bacterium Akkermansia muciniphila : A sentinel for gut permeability and its relevance to HIV-related inflammation.

Front Immunol. Özkul C, Yalınay M, Karakan T. Islamic fasting leads to an increased abundance of Akkermansia muciniphila and Bacteroides fragilis group: A preliminary study on intermittent fasting.

Turk J Gastroenterol. American Academy of Family Physicians. Intermittent fasting. Forslund SK. Fasting intervention and its clinical effects on the human host and microbiome. J Intern Med. Poggiogalle E, Jamshed H, Peterson CM. Circadian regulation of glucose, lipid, and energy metabolism in humans.

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List of Partners vendors. Wellness Nutrition. By Marnie Schwartz. Medically reviewed by Melissa Nieves, LND. Melissa Nieves, LND, RD, is a registered dietitian with Practical Nutrition, LLC.

She also works as a bilingual telehealth dietitian for Vida Health Program. learn more. Trending Videos. What Is Dirty Fasting—And How Is It Different From Clean Fasting? Was this page helpful? Thanks for your feedback!

Tell us why! For the rest of the study, the researchers interspersed the days of regular baseline energy intake with days where the participants had severely restricted energy intake formulated by a clinical dietitian.

They also recorded their body weight , waist circumference, body fat , systolic blood pressure, and diastolic blood pressure at each time point. During the study, participants lost, on average, 7. And at the end of phase II, their gut microbial diversity had increased from the baseline.

However, at the end of phase III, there was no significant difference from the start of the study. There were also some changes in the species making up the gut microbiota, with a decrease in Escherichia coli and an increase in Faecalibacterium prausnitzii, Parabacteroides distasonis, and Bacteroides uniforms.

Kelsey Costa , a registered dietitian and nutrition consultant for the National Coalition on Healthcare, who was not involved in the study, explained how these changes in gut bacteria might affect health:.

prausnitzii is one of the most abundant bacteria in the gut and is generally associated with good health and immunity. distasonis is associated with breaking down carbohydrates and producing useful metabolites.

This bacteria is known to thrive in a diet rich in fiber. uniformis is known to have anti-inflammatory properties and plays a role in processing complex sugars in our diet. The researchers noted that these changes were associated with significant reductions in the activity of brain regions implicated in the regulation of appetite and addiction.

However, they do not explain what effect these changes are likely to have on appetite. In a press release, co-author Dr. Xiaoning Wang from the Institute of Geriatrics of the PLA General Hospital stated:.

The microbiome produces neurotransmitters and neurotoxins, which access the brain through nerves and the blood circulation.

In return, the brain controls eating behavior, while nutrients from our diet change the composition of the gut microbiome. As an observational study, this research cannot show a causal relationship between IER, weight loss, and the gut microbiome, but it does provide more evidence of a link. The researchers suggest that long-term dietary intervention should be used to maintain weight loss and further clarify the relationship between the gut microbiome and the brain, and Costa agreed.

There is a lot of hype around intermittent fasting, but what are its actual benefits, and what are its limitations? We lay bare the myths and the….

Is it true that breakfast is the most important meal of the day? What will happen if you choose to skip breakfast?

But at this point, there are still a lot of gaps in the science. The migrating motor complex refers to recurrent cycles of powerful contractions that sweep the contents of the gut, including its bacteria, down into the colon.

Essentially, this motor complex behaves like a street-cleaning crew tidying up after a parade. It ensures the gut is cleared out and cleaned up in between meals, via minute repeating cycles that fasting allows to be become more frequent.

Ideally, Mayer says people could for the most part adhere to the kind of time-restricted eating program that allows a full to hours each day for the motor complex to work.

In other words, sticking to three meals a day and avoiding between-meal bites or nighttime snacks could be sufficient. Read More: The Truth About Fasting and Type 2 Diabetes.

Some researchers have called it a helpful housekeeping mechanism, and it occurs naturally when the body goes without energy calories for an extended period of time. But these improvements have not yet been demonstrated in real-world clinical trials involving people.

Eran Elinav, principal investigator of the Host-Microbiome Interaction Research Group at the Weizmann Institute of Science in Israel. This is likely to have health implications, though what those are, precisely, remains murky. Read More: What We Know About Leaky Gut Syndrome. Figuring out whether fasting could also lead to longer-term improvements is just one of many questions that needs to be answered.

While plenty of unknowns remain, experts say that common approaches to fasting appear to be safe for most people. Even among people with metabolic diseases such as Type 2 diabetes, research suggests that this form of fasting is safe, provided a person is not taking blood-glucose medications.

Also, there is very little research on more extreme forms of fasting, such as plans that involve going without calories for several days at a stretch. These diets may turn out to be therapeutic, but they could also turn out to be dangerous.