Is the Ketogenic Diet Safe?

Written by Dr. Steve Chaney on . Posted in Ketogenic Diet

Is The Ketogenic Diet Effective?

Author: Dr. Stephen Chaney

ketogenic dietThe ketogenic diet has been around for a while. It has been used to control epilepsy in children since the 1920s. Nobody is quite sure why it helps control epilepsy, but it does. Once a mainstay of therapy, it is now primarily used as an adjunct to anti-epileptic drugs.

However, recently the ketogenic diet has gone mainstream. It’s no longer just for epilepsy. It has become the latest diet fad. If you believe the claims:

  • Hunger and food cravings will disappear. The pounds will melt away effortlessly and rapidly.
  • You will feel great. You’ll have greater mental focus and increased energy.
  • Physical endurance will increase. You’ll become superhuman.
  • Type 2 diabetes will disappear.
  • Your blood sugar, cholesterol, and triglyceride levels will improve, reducing your risk of developing diabetes and heart disease.

What’s not to like? This sounds like the perfect diet. But, are these claims true? More importantly, is this diet safe?

What Is Ketosis?

what is ketosisKetosis is a natural metabolic adaptation to starvation. To better understand that statement let me start with a little of what I’ll call metabolism 101.

Metabolism 101:

The Fed State: Here’s what happens to the carbohydrate, protein & fat we eat in a meal.

  • Most carbohydrates are converted to blood sugar (glucose), which is utilized in three ways:
    • Most tissues use glucose as their primary energy source in the fed state.
    • Excess glucose is stored as glycogen in muscle and liver.
    • Glycogen stores are limited, so much of the excess glucose is stored as fat.
  • A few tissues such as heart muscle use fat as an energy source. Excess fat is stored.
  • Protein is also used in three ways:
    • Some of it is used to replace and repair the protein components in muscle and other tissues.
    • In conjunction with exercise, protein can be used to increase muscle mass.
    • Excess protein is converted to fat and stored.

The Fasting State: Between meals:

  • Most tissues switch to fats as their primary energy source. Fat stores are utilized to fuel the cells that can use fat.
  • Brain, red blood cells, and a few other tissues still rely solely on glucose as their energy source.
    • Liver glycogen stores are broken down to keep blood glucose levels constant and provide energy for these tissues. (Muscle glycogen stores are reserved for high intensity exercise).
    • As liver glycogen stores are depleted, the body starts breaking down protein and converting it to glucose.

ketogenic diet problems and solutionsStarvation – The Problem: If the fasting state were to continue for more than a few days, we enter what is called starvation. At this point we have a serious problem. Fat stores and carbohydrate stores (liver glycogen) exist for the sole purpose of providing fuel during the fasting state. Protein, however, is unique. There are no separate protein stores in the body. All protein in our body is serving essential functions.

To make matters worse, our brain is metabolically very active. It consumes glucose at an alarming rate. Thus, large amounts of glucose are needed even in the fasting state. If protein continued to be converted to glucose at the same rate as during an overnight fast, our essential protein reserves would rapidly be depleted. Irreversible damage to heart muscle and other essential organs would occur. We would be dead in a few weeks.

Starvation – The Solution: Fortunately, at this point a miraculous adaptation occurs. Our bodies start to convert some of the fat to ketones.

  • All tissues that use fat as an energy source during fasting can also use ketones as an energy source, sometimes with greater efficiency.
  • Over a period of several days, the brain adapts to ketones as its primary energy source. This greatly reduces the depletion of cellular protein to supply blood glucose.
  • However, red blood cells and a few other cells still require glucose as an energy source. Essential protein reserves are still being depleted, but at a far slower pace.
  • With these adaptations, humans can survive months without food if necessary.

There are a few other adaptations that make sense if we think about the dilemma of going long periods without food.

  • Appetite decreases.
  • Metabolic rate decreases, which helps preserve both protein & fat stores.

 

What Is The Ketogenic Diet?

 

ketogenic diet keytonesProponents of the ketogenic diet advocate achieving a permanent state of ketosis without starving yourself. That is achievable because the real trigger for ketosis is low blood sugar, not starvation.

The starting point for the ketogenic diet is low-carb, high-fat diets like Atkins. However, ketogenic diets go beyond traditional low-carb, high-fat diets. They restrict carbohydrates even further to <10% of calories so that a permanent state of ketosis can be achieved. Basically, the ketogenic diet:

  • Eliminates grains and sugars.
  • Eliminates most fruits.
  • Eliminates starchy vegetables (root vegetables, corn, peas, beans, squash & yams).
  • Reduces protein intake. That’s because dietary protein will be converted to glucose when blood glucose levels are low.

You are left with a highly restrictive diet that allows unlimited amounts of fats & some vegetables and moderate amounts of meats, eggs, and cheeses.

The Ketogenic Diet Is Not For Wimps

ketogenic diet tough#1: You have to be committed. As noted above, this is a highly restrictive diet. You will have great difficulty following it when you eat out or are invited to a friend’s house for dinner. You will also have to give up many of your favorite foods.

#2: The transition is rough. Physiological adaptation to the ketogenic diet will take anywhere from a couple of days to a week or two. During that time, you will have to endure some of the following:

  • Headaches, confusion & “brain fog”
  • Fatigue
  • Hunger
  • Lightheadedness and shakiness
  • Leg cramps
  • Constipation
  • Bad breath
  • Heart palpitations

#3: There are no “cheat days”. On most diets, you can have occasional “cheat days” or sneak in some of your favorite foods from time to time. The ketogenic diet is different. A single “cheat day” is enough to take you out of ketosis. If you want to resume the ketogenic diet, you will need to go through the transition period once again.

Is The Ketogenic Diet Effective?

ketogenic diet effectiveWith this background in mind, let’s evaluate the claims made by proponents of the ketogenic diet. I’ll rate them on the “Pinocchio Scale”. “Zero Pinocchios” means they are mostly true. “One Pinocchio” means they are half true. “Two Pinocchios” means they are mostly false.

Zero Pinocchios (Mostly True Claims):

  • Reduced hunger. This is part of the starvation response.
  • Improved mental focus and increased energy. In part, this is simply in contrast to the “brain fog” and fatigue of the transition phase. However, you have also eliminated all foods that can cause blood sugar swings from your diet. Blood sugar swings can affect both mental focus and energy levels.
  • Rapid weight loss. If we focus on short term weight loss, this is true because:
    • A lot of the initial weight loss is water. Glycogen stores retain water. As glycogen stores are depleted, the water is lost along with them.
    • Most people inadvertently reduce their caloric intake on a highly restrictive diet like this. For example, fats are often consumed along with carbohydrate-rich foods (butter with toast, sour cream with potatoes, cream cheese with bagels). While it is easy to say that unlimited consumption of healthy fats is allowed, most people reduce their consumption of fats in the absence of their carbohydrate-rich companions.
    • Note: Proponents of the ketogenic diet will tell you that the weight loss associated with the ketogenic diet is because you are burning fat stores. You will only burn fat stores when dietary fat intake is not sufficient to meet your energy needs. In other words, you burn your fat stores when “calories in” are less than “calories out” – just as with any other diet.
  • Reversal of type 2 diabetes. Because carbohydrates are restricted in this diet, blood sugar and insulin levels will be low. If you are on medications, those will need to be adjusted by your physician.

 

One Pinocchio (Half-True Claims):

  • Improved cholesterol and triglyceride levels. The jury is out on this one. Some studies show an improvement on the ketogenic diet. Other studies show them getting worse.
  • Increased physical endurance. This is only true for low-intensity endurance exercise. It is not true for any exercise or event that requires spurts of high intensity exercise. That’s because:
    • The muscle fibers used for low intensity endurance exercise utilize ketone bodies with high efficiency. That means you can run for miles as long as you don’t care how fast you get there.
    • The muscle fibers used for high-intensity, short-duration exercise cannot adapt to use of ketone bodies because they lack sufficient mitochondria. They require glycogen stores, which are depleted on a ketogenic diet. Even in endurance events like marathons most people want to sprint to the finish line. They won’t be able to do that if they are on a ketogenic diet.

 

Two Pinocchios (Mostly False Claims):

  • ketogenic diet mythsLong term weight loss. Some long-term success has been claimed in a highly controlled clinical setting. However, most studies show:
    • People regain some or most of the weight after 6 months to a year.
    • After 1 or 2 years, there is no difference in weight loss between high-fat/low-carb diets and low-fat/high-carb diets.
    • That’s because:
      • Most people cannot stick to restrictive diets long term, and this diet is very restrictive.
      • Once you go off this diet, even for a short time, your glycogen stores will be replenished and the water weight will return along with the glycogen.
      • The reduction in metabolic rate and the reduction in muscle mass associated with the ketogenic diet make it difficult to keep the weight off long term
  • It is a healthy diet.
    • This is a healthy diet only from the point of view that it eliminates most fast foods and processed foods.
    • However, any diet that eliminates 2 and a half food groups (grains, fruits, and starchy vegetables) is setting you up for long term nutritional deficiencies. It is possible to cover some of those deficiencies with supplementation, but supplements can never provide all the nutrients found in real food.

 

Is The Ketogenic Diet Safe?

ketogenic diet safeFor most people the ketogenic diet is likely to be safe for short periods, maybe even a few months. However, I have grave concerns if the diet is continued long term.

  • I have already mentioned the likelihood this diet will create nutritional deficiencies. Long term, those deficiencies could have severe health consequences.
  • Proponents of the diet recommend that protein intake be limited so that “optimal” ketosis can be achieved. If the dieter is successful at doing that, it will result in a gradual depletion of essential cellular protein reserves as discussed above. Long term, that has the potential to weaken heart muscle, compromise the immune system, and damage essential organs.
  • Ketones can damage the kidneys. In the short term, damage is likely to be minimal as long as plenty of water is consumed. However, long term ketosis could be a significant concern for your kidneys.

I have seen proponents of the ketogenic diet shrug this off as a concern only if protein intake is excessive. They are missing the point. The problem is the ketones, not the protein.

  • Long term ketosis has the potential to cause osteoporosis. That is because the so-called “ketones” are actually organic acids except for the small amount of acetone that gives your breath a fruity smell. Organic acids must be neutralized to keep our body pH in the normal range. There are multiple mechanisms for neutralizing organic acids. One of those mechanisms involves dissolving bone and releasing calcium carbonate into the bloodstream. This slow dissolution of bone will continue for as long as someone is in ketosis.

 

Proponents of the ketogenic diet shrug this off by saying that you never get into ketoacidosis on their diet. Again, they are missing the point. Ketoacidosis simply means that the production of organic acids has become so great that all the body’s mechanisms for neutralizing those acids have become overwhelmed. Ketoacidosis occurs in uncontrolled diabetes and can be deadly. The problem is the slow dissolution of bone during long term ketosis, not a short-term crisis like ketoacidosis.

If you are considering the ketogenic diet for weight loss, my recommendations would be to:

  • Consider other equally effective, but less demanding, weight loss programs. Look for programs that help you preserve muscle mass and teach you healthy eating habits that can be sustained for a lifetime.
  • If you do decide to follow the ketogenic diet, only use it for a short period of time to jump start your weight loss. Then switch to a diet program that has been clinically proven to improve your health long term. Examples would be the Mediterranean diet and the Dash diet.

If you are choosing the ketogenic diet for health reasons, I would recommend the Mediterranean diet or Dash diet instead.

 

The Bottom Line

 

  1. The ketogenic diet is the latest diet fad. I give it a C+ compared to other popular diets.
  2. This is not a diet for wimps.
    • It is a highly restrictive diet
    • The transition period as you adjust to the diet is rough.
    • There are no “cheat days”
  3. Some of the claims made for the ketogenic diet are mostly true, some are half-true, and some are mostly false. I help you sort them out in the article above.
  4. Short term, the diet is probably safe for most people. However, long term I have several concerns.
    • The diet is likely to create nutritional deficiencies. Long term, those deficiencies could have severe health consequences.
    • The diet is likely to gradually deplete essential cellular protein reserves. Long term, that could weaken heart muscle, compromise the immune system, and damage essential organs.
    • The diet has the potential to damage the kidneys.
    • The diet has the potential to cause osteoporosis.
    • The metabolic rationale for those concerns is discussed in the article above.
  5. If you are considering the ketogenic diet for weight loss, my recommendations would be to:
    • Consider other equally effective, but less demanding, weight loss programs. Look for programs that help you preserve muscle mass and teach you healthy eating habits that can be sustained for a lifetime.
    • If you do decide to follow the ketogenic diet, only use it for a short period of time to jump start your weight loss. Then switch to a diet program that has been clinically proven to improve your health long term. Examples would be the Mediterranean diet and the Dash diet.
  6. If you are choosing the ketogenic diet for health reasons, I would recommend the Mediterranean diet or Dash diet instead.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Comments (11)

  • Eroca Zeviar

    |

    Love your detailed specicifity and clarity. With so many group things online ie Betrayal system and group anti cancer infos, many different diets being promoted without the public really knowing enough to make an informed choice based on real proven knowledge.

    Thanks for your valued presentation.

    Reply

  • Merlena Cushing

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    Thank you so much for an incredibly compelling and thorough article. I will simply say I second the accolades given by Eroca…she put it very well. We are indebted to you for your continued articles here and on FB and your generosity in sharing them with all of us. Bless you!

    Reply

  • Judy LaBrune

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    Thank you for clarifying the Ketogenic diet! I’ve heard several people talking about how great it is. This article will be very helpful in sharing the myths and truths.

    judy

    Reply

  • Bonnie zeman

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    We use keto but it is with two life shakes a day. Also the life strip. I suppose it is not true keto. But they are losing a pound a day. We really pay attention to fats, butter, mayo, 100% cold pressed virgin olive oil and coconut oil. Purified water every hour. So far it has worked great. All top grade meats, fish, chicken and eggs. And huge amts of veggies. We also check on them every week.

    Reply

    • Dr. Steve Chaney

      |

      Dear Bonnie,
      It looks more like the Atkins diet to me. As I said in the article, it will succeed short term, but it will be hard to maintain that weight loss long term. I would also remind you that the only diets proven to be healthy long term are the Mediterranean and DASH.
      Dr. Chaney

      Reply

  • Justin Carlson

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    Dr. Chaney I appreciate your efforts of looking into the ketogenic diet, which indeed is becoming popular, but many of your conclusions seems to be based on speculation and lack scientific backing. It also seems unfair to call the diet a fad, when it is used as a treatment for many medical conditions today (chronic fatigue syndrome, neurodegenerstive diseases, etc.) due to the increased energy that ketones yield per unit compared to glucose. Instead of brushing this diet off as a fad, you should be treating it as a legitimate diet and give specific advice on how to eat properly and get the right nutrition when in ketosis. I think that would be most beneficial for your readers.

    Reply

    • Dr. Steve Chaney

      |

      Dear Justin,

      I did open my article by saying that the keto diet was well established for treatment of epilepsy in children. I am also aware of the research into its use for other neurodegenerative disorders. It is not as well established for those uses, but the research is promising. If my article was focused on those uses of the keto diet, it would have been completely appropriate to discuss how to follow it.

      I was focusing on the current usage of the diet to lose weight and to promote long term health. Those applications of the keto diet are unproven at present. The studies to date support short term weight loss and the improvement of blood parameters that may or may not equate with long term health outcomes. At this point we have no long term studies showing that the weight loss is maintained long term or that there is an improvement in health outcomes long term. Until we have that kind of evidence, I think it is appropriate to consider it a fad diet.

      Dr. Chaney

      Reply

  • Bill Moore

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    Interesting. I’ve been on a keto diet for 4 years now and pretty much all the ‘1 and 2’ Pinocchio’s you claim simply aren’t so. I know many (many) people that have stayed on this diet for years and are very happy with it. Is it difficult? Not at all. Does society do it’s absolute best to make it difficult? Very much so.

    You should try reading what people actually doing this diet say vs. a doctor who is, clearly, biased against something he doesn’t fully understand and, frankly, shouldn’t be writing about.

    If you’d like to see a community of people (over 270,000 of them) on keto, go here: https://www.reddit.com/r/keto/ You’ll find many people that can give you actual real world facts as well as the science behind why it works and why it works long term.

    If you’re a science geek, go talk to the 14,000 plus PhD’s and keto nerds who study this stuff for a living here: https://www.reddit.com/r/ketoscience/

    Reply

    • Dr. Steve Chaney

      |

      Dear Bill,

      Let me start by reminding you of my credentials. I taught human metabolism and nutrition to medical students for 40 years, and received numerous teaching awards during that time period. It is fair to say that I am an expert on human metabolism and how that metabolism is affected by our diet.

      I appreciate that your experiences with the keto diet have been positive, and that there is a small community of adherents who have also had positive experiences. In the scientific community, we call those case reports and consider them the least reliable level of proof. Scientists prefer to do clinical studies to see if the same observations are true for the majority of people who follow the diet. For example, it is clear from existing clinical studies that most people who follow the diet achieve short term weight loss, which is why I recommended it for that purpose. However, the important question is whether most people can stick with the diet long enough to maintain that weight loss for two years or more. I laud you for your discipline of being able to stick with the diet for 4 years, and I suspect you have managed to maintain your weight loss. However, until I see published clinical studies showing that most people who embark on the keto diet maintain their weight loss for two years or more, I cannot recommend it for that purpose, and it deserves 2 pinocchios.

      As for the 1 pinocchios, even the proponents of the keto diet say that it is good for endurance exercise, but not for things like sprinting. As for the cholesterol and triglyceride levels, most proponents of the keto diet conveniently ignore the fact that not all reports support improved levels. Personally, I think that is likely to be the case, but we need to remember that improvements in cholesterol and triglyceride levels may or may not translate into improved health outcomes. Until long term studies on health outcomes have been conducted, we cannot claim the keto diet is healthy.

      Dr. Chaney

      Reply

  • Paul

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    I would like to see the research that you talk about but don’t quote! It seems you are one of the many not up with numerous studies showing the many benefits of a ketogenic diet. It is not hard and if you call not eating grains restrictive, you obviously don’t know what a well-formulated keto diet is. You can even do keto as a vegan if you don’t want to eat animal products. When you break down triglycerides, the glycerol back bone is converted into glucose, so you always have enough glucose for the brain. I could go on, but seriously check to see what many Doctors that understand this diet are saying like Dr Mercola.

    Reply

    • Dr. Steve Chaney

      |

      Dear Paul,

      Let me start by reminding you of my credentials. I taught human metabolism and nutrition to medical students for 40 years, and received numerous teaching awards during that time period. It is fair to say that I am an expert on human metabolism and how that metabolism is affected by our diet.

      I am aware of studies on the benefits of the keto diet and referred to some of them in my article. Those are all short term studies, and do not provide evidence for long term health outcomes. For example, unless there are published studies showing that most people can stick to a diet and maintain weight loss for at least one or two years, it cannot be recommended as a successful weight loss approach. Similarly, there are studies showing that adhering to a Vegan, Mediterranean, or DASH diet over decades results in improved health outcomes (lower prevalence of heart disease, cancer & diabetes). In spite of the fact that high fat, low carb diets have been around since the 50s, I am unaware of a single study showing they result in improved long-term health outcomes. In the absence of that kind of evidence, they cannot be recommended as healthy diets.

      If the keto diet simply eliminated grains, it might would be more acceptable. However, most descriptions of the keto diet I have seen also restrict starchy vegetable, most fruits, and legumes. With that kind of restriction (especially the legumes), it is hard to see how a Vegan diet and the keto diet would be compatible.

      You can get some glucose from the glycerol backbone, but that is not enough to supply the body’s needs. That is why many of the description of the keto diet also recommend that you restrict protein.

      Dr. Chaney

      Reply

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Latest Article

Is Our Microbiome Affected By Exercise?

Posted November 6, 2018 by Dr. Steve Chaney

Microbiome Mysteries

Author: Dr. Stephen Chaney

is our microbiome affected by exerciseIn a recent post,  What is Your Microbiome and Why is it Important,  of “Health Tips From The Professor” I outlined how our microbiome, especially the bacteria that reside in our intestine, influences our health. That influence can be either good or bad depending on which species of bacteria populate our gut. I also discussed how the species of bacteria that populate our gut are influenced by what we eat and, in turn, influence how the foods we eat are metabolized.

I shared that there is an association between obesity and the species of bacteria that inhabit our gut. At present, this is a “chicken and egg” conundrum. We don’t know whether obesity influences the species of bacteria that inhabit our gut, or whether certain species of gut bacteria cause us to become obese.

Previous studies have shown that there is also an association between exercise and the species of bacteria that inhabit our gut. In particular, exercise is associated with an increase in bacteria that metabolize fiber in our diets to short chain fatty acids such as butyrate. That is potentially important because butyrate is a primary food source for intestinal mucosal cells (the cells that line the intestine). Butyrate helps those cells maintain the integrity of the gut barrier (which helps prevent things like leaky gut syndrome). It also has an anti-inflammatory effect on the immune cells that reside in the gut.

However, associations don’t prove cause and effect. We don’t know whether the differences in gut bacteria were caused by differences in diet or leanness in populations who exercised regularly and those who did not. This is what the present study (JM Allen et al, Medicine & Science In Sports & Exercise, 50: 747-757, 2018 ) was designed to clarify.  Is our microbiome affected by exercise?

 

How Was The Study Designed?

is our microbiome affected by exercise studyThis study was performed at the University of Illinois. Thirty-two previously sedentary subjects (average age = 28) were recruited for the study. Twenty of them were women and 12 were men. Prior to starting the study, the participants filled out a 7-day dietary record. They were asked to follow the same diet throughout the 12-week study. In addition, a dietitian designed a 3-day food menu based on their 7-day recall for the participants to follow prior to each fecal collection to determine species of gut bacteria.

The study included a two-week baseline when their baseline gut bacteria population was measured, and participants were tested for fitness. This was followed by a 6-week exercise intervention consisting of three supervised 30 to 60-minute moderate to vigorous exercise sessions per week. The exercise was adapted to the participant’s initial fitness level, and both the intensity and duration of exercise increased over the 6-week exercise intervention. Following the exercise intervention, all participants were instructed to maintain their diet and refrain from exercise for another 6 weeks. This was referred to as the “washout period.”

VO2max (a measure of fitness) was determined at baseline and at the end of the exercise intervention. Stool samples for determination of gut bacteria and concentrations of short-chain fatty acids were taken at baseline, at the end of the exercise intervention, and again after the washout period.

In short, this study divided participants into lean and obese categories and held diet constant. The only variable was the exercise component.

 

Is Our Microbiome Affected By Exercise?

is our microbiome affected by exercise fitnessThe results of the study were as follows:

  • Fitness, as assessed by VO2max, increased for all the participants, and the increase in fitness was comparable for both lean and obese subjects.
  • Exercise induced a change in the population of gut bacteria, and the change was comparable in lean and obese subjects.
  • Exercise increased fecal concentrations of butyrate and other short-chain fatty acids in the lean subjects, but not in obese subjects.
  • The exercise-induced changes in gut bacteria and short-chain fatty acid production were largely reversed once exercise training ceased.

The authors concluded: “These findings suggest that exercise training induces compositional and functional changes in the human gut microbiota that are dependent on obesity status, independent of diet, and contingent on the sustainment of exercise.” [Note: To be clear, the exercise-induced changes in both gut bacteria and short-chain fatty acid production were independent of diet and contingent on the sustainment of exercise. However, only the production of short-chain fatty acids was dependent on obesity status.]

 

What Does This Study Mean For You?

is our microbiome affected by exercise gut bacteriaThere are two important take home lessons from this study.

  • With respect to our gut bacteria, I have consistently told you that microbiome research is an emerging science. This is a small study, so you should regard it as the beginning of our understanding of the effect of exercise on our microbiome rather than conclusive by itself. It is consistent with previous studies showing an association between exercise and a potentially beneficial shift in the population of gut bacteria.

The strength of the study is that it shows that exercise-induced changes in beneficial gut bacteria are probably independent of diet. However, it is the first study to look at the interaction between obesity, exercise and gut bacteria, so I would interpret those results with caution until they have been replicated in subsequent studies.

  • With respect to exercise, this may be yet another reason to add regular physical activity to your healthy lifestyle program. We already know that exercise is important for cardiovascular health. We also know that exercise increases lean muscle mass which increases metabolic rate and helps prevent obesity. There is also excellent evidence that exercise improves mood and helps prevent cognitive decline as we age.

Exercise is also associated with decreased risk of colon cancer and irritable bowel disease. This effect of exercise has not received much attention because the mechanism of this effect is unclear. This study shows that exercise increases the fecal concentrations of butyrate and other short-chain fatty acids. Perhaps, this provides the mechanism for the interaction between exercise and intestinal health.

 

The Bottom Line

A recent study has reported that:

  • Exercise induces a change in the population of gut bacteria, and the change was comparable in lean and obese subjects.
  • Exercise causes an increase in the number of gut bacteria that produce butyrate and other short-chain fatty acids that are beneficial for gut health.
  • These effects are independent of diet, but do not appear to be independent of obesity because they were seen in lean subjects but not in obese subjects.
  • The exercise-induced changes in gut bacteria and short-chain fatty acid production are largely reversed once exercise training ceases.

The authors concluded: “These findings suggest that exercise training induces compositional and functional changes in the human gut microbiota that are dependent on obesity status, independent on diet, and contingent on the sustainment of exercise.”

For more details and my interpretation of the data, read the article above.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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