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Could a Leaky Gut Be Making You Fat?


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It’s no secret that obesity, diabetes, and metabolic disease are afflicting an incredible number of Americans; in fact, the prevalence of the metabolic syndrome in our country has reached an astonishing 34% and is continuing to rise. (1) This disease, characterized by long term low-grade inflammation, causes metabolic disturbances that lead to the development of complications such as nonalcoholic fatty liver disease, cardiovascular disease, and type 2 diabetes. This is a serious health problem for many Americans – one that isn’t going away any time soon – and determining the cause of these metabolic conditions is a top priority for obesity researchers across the country.

I’ve been writing about the connection between gut health and “diabesity” for quite some time now; I have an entire series on diabesity and metabolic syndrome on my website dedicated to the relationships between obesity, insulin resistance, metabolic syndrome and type 2 diabetes, and I believe that inflammation and leaky gut caused by gut dysbiosis are the key players in this metabolic epidemic. While the existence of leaky gut syndrome is still debated among doctors and scientists, it is clear to me that having healthy gut bacteria is crucial to maintaining a normal weight and functional metabolism.

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Recently, a group of researchers in Brazil published a new review exploring the idea that intestinal permeability is a contributing factor to obesity.

They identified three separate but related mechanisms: gut dysbiosis, an unhealthy dietary pattern, and specific nutrient deficiencies. These three risk factors likely interact to cause intestinal permeability and promote the development of the metabolic syndrome and obesity.

Gut Dysbiosis and Leaky Gut

It is well documented that those with obesity have significantly impaired gut function compared to the general population. Obese individuals are shown to have problems with effective digestion and absorption of food, gastrointestinal illness, unstable or pathological intestinal microbiota, poor immune status, and overall lower wellbeing, suggestion a lack of gut health. (2) This gut dysbiosis is thought to cause increased permeability in the small intestine, allowing the entry of toxins called lipopolysaccharides (LPS) into the blood and triggering systemic inflammation.

While it is uncertain whether the alterations in gut health are the cause or consequence of obesity, the association between dysbiosis and obesity is strong.

One theory is that the metabolic activity of gut microbiota contributes to weight gain by causing more calories to be extracted from the food passing through the gut. Small intestinal bacterial overgrowth (SIBO) may also play a role in intestinal permeability by increasing constipation, reducing pancreatic enzyme and gastric acid activity, and disturbing the microbiota and host immune system relationship.

Probiotic supplementation can help strengthen the tight junctions of the intestine, reducing overall permeability. Probiotics can have anti-inflammatory effects in the gut, regulating the production of inflammatory cytokines and reducing intestinal permeability. This demonstrates the benefits of a balanced microbiota in the gut to maintain the function of the intestinal barrier, particularly in obesity.

Dietary Effects on Leaky Gut

Besides just the composition of gut bacteria, nutritional factors play an important role in permeability as well. The authors of this study suggest that there are two major components of the diet that can affect intestinal permeability: fructose and fat. Fructose is thought to damage the liver directly by increasing blood levels of LPS toxins, causing fatty liver, inflammation, and hepatic insulin resistance. These effects explain why high fructose consumption has been implicated in the development of metabolic syndrome.

As far as fat goes, the authors of this study suggest that fat is more efficient than carbohydrates at transporting LPS toxins to the liver through the formation of chylomicrons, molecules that deliver dietary fats from digestion to the liver. An increase in liver toxins was demonstrated to induce obesity, diabetes, and insulin resistance in rats, demonstrating why a high fat diet could exacerbate metabolic disease. The type of fat matters though; oleate, a monounsaturated fat, promotes the delivery of toxins to the liver, while butyrate, a short chain saturated fat, does not form chylomicrons or increase LPS toxins in the liver. It has also been found that changes in bile secretion are associated with altered intestinal permeability, and a decrease in bile allows for greater bacterial growth in the small intestine and more LPS being produced.

It is important that future research determine the type of fatty acids that increase intestinal permeability of endotoxins, and whether or not there is an interaction with the type and amount of bacteria in the gut.

The authors of this review do suggest, however, that a combination of a high fructose and high fat diet can lead to an increase in toxin-related liver inflammation and weight gain, which is likely true. (Did someone say McDonald’s Value Meal?)

Nutritional Deficiencies and Leaky Gut

There are several micronutrient deficiencies that the authors found to be associated with gut barrier function, specifically vitamin A, magnesium, zinc, vitamin D, and calcium. Vitamin A, zinc, and magnesium all help maintain tight junctions in the intestine and regulate endothelial differentiation in the gut, while vitamin D stimulates intestinal lining renewal and resistance to damage by modulating the immune system. Vitamin D and calcium play a joint role in maintaining the intestinal barrier by supporting the ATP-dependent pumps in the intestinal cells. In obesity, intake of these micronutrients is typically low, so deficiencies could play a significant role in exacerbating leaky gut conditions, especially when combined with intestinal dysbiosis and poor dietary choices. Therefore, having good intake of these micronutrients could be protective against the development of leaky gut and the inflammation and eventual obesity it can cause.

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Obesity Caused by a Leaky Brain?

One more potential issue (not discussed by this particular review paper) is the possibility that systemic inflammation can actually cause leakiness in the blood-brain barrier as well. (3)

C-reactive protein (CRP), an inflammatory protein that is elevated in obesity, has been found to increase permeability of the blood-brain barrier, possibly leading to inflammation in the hypothalamus. This neuroinflammation can cause impairment of central nervous system (CNS) function, which has been associated with poor control of food intake, leptin resistance, and obesity.

Furthermore, LPS toxins, released into the blood by a leaky gut, can rapidly increase blood leptin concentrations; this increase is enhanced by the presence of CRP, which could explain why chronic inflammation is associated with a rise in both CRP and leptin in humans. In this way, a leaky gut and a leaky brain, both caused by systemic inflammation and exacerbated by gut dysbiosis, can increase the risk of developing obesity due to the disruption in CNS and leptin function.

Gaining Weight? Check Your Gut Health!

The take home message of this study is that the interplay of gut health and diet has a significant role in weight gain and risk of obesity and metabolic disease. If you are struggling to lose weight, you may be dealing with inflammation caused by leaky gut and dysbiosis. And remember, you don’t have to have gut symptoms to have a leaky gut! Weight gain alone could be your only symptom, but it’s an important one to consider.

There are many steps you can take to ensure a healthy gut. Using probiotics and prebiotics can change the quality of the microbiome in the gut, and there are certain dietary strategies that can help improve the strength of the tight junctions between intestinal cells. Other issues such as stress, antibiotic and other medication use, autoimmune disease, and dietary toxins can increase intestinal permeability, so these are gut health factors that must be addressed as well.

Just be sure that you take the necessary steps heal your gut if you’re struggling with weight loss despite making changes in your diet and lifestyle. It may be the last piece in the weight loss puzzle that you’re missing!

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Join the conversation

  1. The problem with treating leaky gut is that it can cause histamine intolerance and two of the most “healing things” namely glutamine and bone broth, are like using gas to put out a fire in this case.

  2. Looking for some feedback. I write about this stuff and still am stuck myself. I’m gaining, gaining, gaining and fear it won’t stop. This year has been heavy detoxing of serious metals poisoning including lead, mercury, arsenic and cadmium. My body took a huge hit and leaky gut was definitely an issue. I’ve danced around the curing of it, but I believe the constant detoxing keeps me in the loop. Meanwhile I’ve gained 20 pounds in a few months….4 weeks of which was while on broth and raw vegetables. Today I’m quitting the small amount of grain and dairy out of fear of gaining any more weight. It is so high now that another set of problems could develop. I suspect it is one jumbled mess, as the lead issues are 20 years old. I’m at the point where I’m weary and can’t afford another trial that ends with error. Encouragement?

    • Susan- I was gaining weigh every week after I started anti depressant. It really messed up my body. Even after I stopped the SSRI I still gained. I also developed joint pain when I stopped the SSRI.
      To the point, I started taking MSM and my gaining stopped that week. It also helped my joint pain tremendously.
      Most info doesn’t site MSM with helping with weight, but it really helped me. It didn’t make me lose, but it did stop the gain.

    • Julia, Do you think the MSM reduced the weight gain because the gain was being caused by inflammation or growth of bad bacteria or parasites?

  3. Chris (or anyone with knowledge) what are your thoughts on lactoferrin for weight issues, i.e. it apparently sequesters iron away from bad bacteria and delivers it to where it’s needed? Also I’ve read a bit that it can bind LPS as well.

  4. I have struggled with severe constipation most of my adult life. After my last child was born, I lost 75lbs. (bringing me down to 125lbs) because I cut out gluten. I have never been “diagnosed” as being intollerant, however, it would not surprise me. I have to say that when I avoid gluten, I feel a lot better. In the last 7 years, the constipation has gotten worse, and I have regained about 40lbs. If I have a BM, it happens once a week if I am lucky. Most recently I went 2 weeks without one. The gas a bloating was so miserable. When I did go, it came out in liquid form. I am going to see a Dr. that is called the ‘Gut Whisperer’ in SLC, UT tomorrow. I have never been excited about going to see a Dr, but I am about seeing this one. My brother’s neighbor was on her death bed and the Dr that she was seeing had no idea what was wrong with her. Turns out, she needed a fecal matter transplant. This ‘Gut Whisperer’ SAVED HER LIFE! I’ll keep you posted on how it goes. I too, would like to lose the weight that diet and exercise has not been successful in removing. Something a lot worse than just lazy eating and behavior is going on.

    • I, too, used to struggle with severe constipation. Going ten days without a bowel movement was not uncommon for me. After going through a leaky gut protocol (basically a version of the auto-immune Paleo protocol) + L-glutamine and taking some other herbs, like oregano and turmeric, and probiotics and cultured veggies, I was able to heal my gut and digestive symptoms. I used to wake up every day with a severe burning stomach, lethargy, fatigue, weight gain, water retention, inflammation (and constipation). Since finishing the protocol, I now permanently stay away from gluten, dairy, and soy. And now, the opposite has occurred…I have actually have had several bouts of diarrhea (which were only temporary and mild, and since cleared). I remember being so grateful for the loose stools after years of constipation…I realize I may be the only one… 😉

    • Fermented foods will give you express eliminations. I use miso soup or kombucha because it is easiest for me to enjoy. Sauerkraut, kimchee and yogurt are not favorites. You could find yourself pooping twice a day.

  5. @T Gregory
    ”..Im done with western medical docs..”
    So true. Western and unfortunately American/Canadian medical doctors are clueless whatsoever. I personally trust only European specialists-naturopaths and homeopaths who have a very long history of medical knowledge and expertise. Even pharmacists in Europe are great at suggesting natural remedies and even sell them at the pharmacies!

    German and British naturopaths and homeopaths are great specialists.
    Gregory, it seems you did alright by removing the problematic foods but you also need to heal your gut with specific natural remedies.
    With my leaky gut issues, I was advised by a German naturopath to drink cabbage juice daily (also eat cultured cabbage) and drink strong infusions of Cistus Incanus and Calendula tea which heal stomach ulcers and intestinal issues. Cistus Incanus (originally from the island of Crete, Greece and only one trusted) is a difficult to find amazing herb which heals all gastrointestinal problems.
    As soon as I drink it I immediately feel its healing power and since I started taking it a month ago I am already 80% healed.
    It can be found at selected sources on ebay and Amazon but make sure the tea is from Greece or Italy and not other countries such as Croatia or Portugal.

    Research and Information on Cistus Incanus:


  6. I have Leaky gut and IR….am now on digestive enzymes and probiotics (Bioceuticals) and have made dietary changes…just wondering how long this regime takes to get the changes required to be well again

    • Seems like forever. I’m making some changes to my program by including probiotics throughout the day. I’m adding fermented foods and trying to replace good bacteria all day. The worst of symptoms are over but the weight stays and I’m not tip-top, so this is the new plan.

      I try to remember that this is a problem that took years to create. I think about the length of the intestines and the distance good bacterial must cover, including all the crevices.
      An exercise in patience or a new lifestyle?

  7. Great article Chris! Unfortunately I aquired a leaky gut from a gluten intolerance and now have numerous other food intolerances from it as well.I have been eating Paleo for about two years and despite having eliminated ALL processed foods, sugar, grains, dairy and beans( I also cant eat nuts and eggs), it continues to get worse and worse for me.I have now suddenly began having issues with meat also due to a possible histamine intolerance.I never knew things could get this bad

    Even with a diet of protein, vegetables and very little fruit I remain 30 pounds overweigt.In trying to make sure theres not something Im doing wrong I keep a calculated food diary and eat between 1250 and 1500 calories per day, exercise and lift weights and still nothing Talk about frustrating. Im about to start on a low histamine/Paleo rotation diet in hopes of that making a difference because I think Im now starting to form allergies to my remaining ‘safe’ foods.

    Im doing everything to heal this leaky gut for the past two years, digestive enzymes, probiotics (that I now cant have due to histamine issues),L-glutamine, and my diets perfect. I only drink spring water and take no meds etc but STILL, just keep losing more food but NO WEIGHT LOSS and tired most of the time.I had a TSH thyroid test a couple years ago that was fine but from what I understand I instead need to be tested for FREE t3, t4 hormones instead but docs wont listen

    .Im done with western medical docs, they are terrible for my type of issue. Ive got to find a good practitioner like you in my area somehow. Does anyone know anyone close to the Virginia area?Sorry I got a bit off topic but I have just been a bit frustrated lately and this article has my name on it!

    Leaky gut is something no one wants to get, I wouldnt wish it on anyone because docs are clueless about it, it comes with a mixed bag of lovely symptoms, an ongoing loss of choice and seems when u get it, it is VERY hard to heal and subject to high rates of relapse. ):

    • T Gregory – You have my sympathy. I developed a leaky gut and gluten intolerance after a quack doctor told me to take Premisol (colloidal silver in pill form) and I got sick as a dog and it left me with what seems like permanent neuropathy.

      As soon as I can get together the $500 I’m going to consult with a homeopath that my friend has had wonderful results with. Here’s a link:

      You don’t have to be local. Everything is done over the phone and by mail. My husband has emphysema, even though he never smoked, and he is just beginning his treatment with Manfred Mueller.

      Good luck,

      • Thanks Laurel, Im so sorry to hear about your case too. I just looked into a functional medicine doc last night and without insurance its 2000 dollars of which I dont have. I will absolutely check into that place you just mentioned as I feel like Im on my last leg here. Have you formed any food intolerances yet from yours? To prevent this or prevent forming any new ones you might wanna look into rotating your foods.Theres a good 5 part series on youtube by Paul chek that explains the whys and how to do it if your interested.Best wishes for health in your case as well and again thanks!

        • T. Gregory – After two years on a gluten-free diet and taking probiotics, I found that I could tolerate gluten again. Initally, I had lots of intestinal trouble (along with other weird and wonderful symptoms), but that cleared up with the Probiotics. Oh, and I ate lots of gelatin and took l-glutamine periodically. Both things are supposed to be healing to the gut. Best of luck!

      • Laurel,

        Just wondering about your husbands results with Dr. Mueller. Did he benefit ? I am thinking of consulting him regarding my mother’s kidney issues.

      • Laurel,
        My neuropathy was caused by heavy metal toxicity. While detoxing and having concentration in the blood it was worse. When blood is clear it disappears. There are causes.

    • T. Gregory–any changes? I’m 2 years into the same problems. Just tested positive for methane producing SIBO and starting 2nd round of antibiotics will follow with intensive anti-inflammatory treatment. Working with licensed naturopathic doctors who specialize in SIBO. Phone consult. siboinfo.com

    • Please eat your last meal before 6:00pm if you are not diabetic.This will cure your leaky gut and weight problems.Please also watch Rajiv Dixit health videos on you tube…

    • It’s over a year later… May I ask, how are you now? Your story here sounds like mine. Did you get any answers or solutions?

    • Try cutting out dairy of any kind, soy and commercial cellulose (hard bc its in most vitamins and meds. ) I found i was autoimmune to those as well as gluten. My SIBO is back but my leaky gut is SOOO much better. I was also diagnosed with Hashimotos so on a vitamin/mineral regime for that, but can only use liquid or a few brands that have no cellulose. The cellulose has been key for me.

  8. This could explain why it is so hard for me to lose weight. I don’t mean the types of foods I eat, since i eat Paleo but it is sooooo hard for me to take the pounds off. I have been on a self-help leaky gut cure and it had done wonders for me but sitll, the pounds are slow to drop off.

    Still, I keep trying by being sure to eat organic as much as possible to eliminate exposure to toxins and eat only natural meats (organic is too expensive). I hope more research is done so that exact correclations to leaky gut can be made to determine the which factors are influencing weight loss resistance.

    Thanks for the article… a good one, to be sure.

  9. The high fructose contribution, is it referring to fructose on it’s own? I think I read somewhere that fructose combined with glucose doesn’t have the same effect. (fruit?)

  10. Interesting article! I’m fairly new to the research on leaky gut. I’ve been struggling with weight gain/loss for years and haven’t been able to crack the code. I am very active and eat healthy, albeit I do not follow Paleo. I have been trying to experiment with different vitamins/supplements to help with weight loss but can’t seem to figure it out. I was recently introduced to the possibilty of leaky gut and metabolic x syndrome. However, the only symptom I seem to have is obesity. I would like to try probiotics. Does anyone have any additional recommendations on either leaky gut, metabolic x syndrome, or which probiotic to use?

    • I eat entire meals of nothing but fruit. I amreally slim. I eat Unllimited carbs from fruit rIce, potatoes . I eat at least 3000 calories a day. Before I eat a lil I was 182 pounds and 22 percent body fat and now weigh 170 pounds and 12 percent fat the mist change occurred over a couple months

  11. There was a paper in Nature recently about enterobacter from an obese person causing obesity when introduced to rodent models. When the obese individual reduced the levels of enterobacter, “the volunteer lost 30.1 kg after 9 weeks, and 51.4 kg after 23 weeks.” I’d love to hear what Chris thinks about this.

    The paper is “An opportunistic pathogen isolated from the gut of an obese human causes obesity in germfree mice”, available at http://www.nature.com/ismej/journal/vaop/ncurrent/full/ismej2012153a.html

  12. In the view of the information presented actions aimed at improving gut health like avoiding coffee and alcohol and sufficient vitamin D level should help with weight management too

  13. and i lost my job dishwashing in prep foods at whole foods cause i couldnt keep up with the other dishwashers.

    now im just super constipated and l i do is lie down all day. im wondering if maybe i developed a new bug.

  14. i have the opposite problem. im having problems eating this week. im severely constipated. yet i lost 4 lbs this week. my weight went from 169 to 165 but my body fat percentage went from 15% to 20%. ive been eating clean paleo with an emphasis towards low fodmaps. i did take two bikram yoga classes this week. and ive been so constipated that i started taking organic acacia gum fiber from helpforibs, it seems to create gas which i wasnt having a problem with and may be worsening the bloat. its funny, i had gone paleo and everything was fine with a daily bm

  15. Chris, do you perform the lactose/mannitol test for leaky gut in your practice? I know you say that before performing a test you ask yourself, “will it affect the outcome of how I treat?”
    but it does seem to be one of the missing links on the paleo diet – the use and presence of bone broth (and from beef bones not from turkey or chicken, as I found those had high levels of fluorine, which caused me problems and apparently high levels of Fluoride ion can contribute to gut permeability as well – From wikipedia, “Ingested fluoride initially acts locally on the intestinal mucosa, where it forms hydrofluoric acid in the stomach.” – Unfortunately there is no source for this, but I found I did have problems with fluoride containing foods, which I ate much more of due to pesticides, and dark meat chicken and turkey on the paleo diet).

    I honestly wonder if leaky gut can also direct you to less nutritious foods. For example, are there studies showing that the casein and giadin opiate type responses are higher in those with leaky gut than those without?

    Or how Paul Jaminet describes it, the cure can make you feel worse some amount of time before you feel better… Thus the greater inability to resist wheat containing products and casein products.

    If you do perform the test, please let me know, and if you could discuss how many of your patients exhibit leaky gut?

    • sorry, the use and presence of bone broth to improve gut mucosal function and obtain valuable bone nutrients is missing on Paleo diet – I hope the post above is more clear.