Dealing with a leaky gut, AKA intestinal permeability is tough.  Adding to the difficulty is figuring out which foods to eat or not eat after you find out you have a leaky gut.

If you haven’t read our post on The Ultimate Guide to Heal Leaky Gut Syndrome Fast, you may want to check it out as we describe in detail the major causes of a leaky gut and the lifestyle changes that best help heal leaky gut. 

But, what if you’re specifically looking for the top leaky gut foods to avoid? Here it is, guta brief, research-backed list of the essential leaky gut foods to avoid and a free leaky gut diet food list PDF so you know the most offensive foods to avoid at all costs.

What are the Top Leaky Gut Foods to Avoid? 

There are a variety of foods that may contribute to leaky gut syndrome for a variety of reasons from impairing digestion, contributing to an imbalance in our good and bad gut bacteria, and more. Below is a leaky gut diet food list that we’ve found both from research and our personal experience. These are the ones we minimize or eliminate when battling a leaky gut:

Picture of wheat and bread which are f
oods that cause leaky gut syndrome

1. Gluten

What the heck is gluten anyways?

Long story short, gluten is a component of grains. More specifically, it is a protein in many grains that acts as a glue in a lot of products AKA bread, pasta, cereals, etc. Ever eat a ton of pizza or pasta and feel like things were slow-moving out the other end the next day? Yep, gluten can really make things sticky and slow transit times down.[1]

Gluten has been heavily researched with Dr. Alessio Fassano leading the way in finding that gluten encourages the body to release Zonulin, which stimulates increased opening between the cells walls of the gut leading to more permeability.

Bags of chips and pretzels which are a "barcode food", one of the worst foods on the leaky gut diet food list.

2. Barcode Food

Boxed and packaged foods are full of preservatives, additives, artificial sweeteners, manufactured sugars like high-fructose corn syrup and more, all of which can contribute to an imbalance in the good and bad bacteria in our gut and exacerbation of leaky gut syndrome. Yes, some produce does come with barcode stickers on it, but you can readily find this food in nature and buy fresh fruit and veggies without them. Cereal and toaster pastries cannot be found in nature and cannot be bought without a barcode.

While many of the chemicals added to processed foods have been tested and are deemed “safe” for human consumption, this does not mean there isn’t consequence or harm that may come with their consumption over time. There is still so much we don’t know. And to be fair, science once told us sucralose (Splenda) and aspartame (NutraSweet) was completely safe to consume in abundance and now we know it is hazardous to gut and brain health, often contributing to neurodegenerative complications and unwanted shifts in the gut microbiome….just saying!![2]

FYI If you would like learn more about the harmful effects of artificial sweeteners, check out our post on 9 Harmful Side Effects of Artificial Sweeteners.

Cupcakes- a leaky gut food to avoid due to high sugar content

3. Sugar

These days sugar comes in a variety of forms- additives like high fructose corn syrup, agave syrup, cane sugar etc. as well in our foods such as in fruits and starchy vegetables like potatoes. The main thing to avoid with sugar is added sugar and binging on excessively sweet or sugary foods. If you like to scarf down fruit all day long or put a load of fruit in your smoothie and avoid veggies or dark leafy greens like the plague, this includes you too!

Why? Well, where should we start? The research is overwhelming and lists a number of ways sugar may add to intestinal permeability…

First, excessive sugar feeds the bad bugs in our stomach leading to dysbiosis. The bad guys grow in numbers, crowd out the good guys, and leaky gut runs rampant. Even more, there is some evidence that the bad guys will stimulate your body to crave more sugar ( in order to continually fuel the bad bugs) which leads to a vicious cycle of bacterial overgrowth–>eating sugar in abundance feeds bacterial overgrowth–>craving more sugar–>repeat.

Another method that sugar effects the bad bugs is by raising our overall blood sugar leading to hyperglycemia which has been found, even in the absence of obesity, to increase intestinal permeability by modification of the tight junction integrity.[3]

Lastly, (there are many more ways sugar effects IP, but we’re going to stop here) the consumption of high levels of fructose in excess of glucose increases IP and allows for increased movement of Lipopolysaccharides (LPS) due to modifying tight junctions, reducing intestinal mucus thickness, and a changing the expression of good antimicrobial proteins in the gut.[4]

But wait, when are we consuming fructose in excess of glucose? Aren’t they usually bonded together in sugar? Well, fructose and glucose are together in a 1:1 ratio in table sugar but let’s not ignore the ratio in HIGH-FRUCTOSE CORN SYRUP?!! HFCS is often 55% fructose and 45% glucose in products such as soft drinks and packaged dessert.

A can of diet Coke and Coca Cola Zero which are a leaky gut food to avoid due to artificial sweeteners

4. Artificial Sweeteners

In our post about the dangers of artificial sweeteners and their harmful side effects, we discuss the research which shows how harmful artificial sweeteners are, how they may contribute to weight gain, heart disease, migraines, and more. But, how do they specifically contribute to leaky gut?

Artificial sweeteners or “Non-caloric artificial sweeteners” (NAS) as its coined in the research, harm the gut by driving, “the development of glucose intolerance through induction of compositional and functional alterations to the intestinal microbiota.”[5] A similar study states that NAS is toxic to the gut by causing inhibition of good bacteria.[6]

Group of dairy foods such as milk, yogurt, and cheese whjich are foods to avoid with leaky gut syndrome.

5. Dairy

This can be a hit or miss depending on quality of product and biochemical individuality, BUT, a majority of adults are intolerant of dairy. In fact, 65 percent of adults have reduced ability to digest lactose after infancy. Even worse, 70-100% of the people from East Asian, West African, Arab, Jewish, Greek, and Italian descent are lactose intolerant.[7]

Let’s also note that there is an incredibly large percentage of the population that has gradually become intolerant to the protein in dairy (whey and or casein) as a result of a gastrointestinal bacterial imbalance over time. So to be clear, for these individuals, lactose (the sugar in milk) is not the issue.

So, what happens when you consume dairy and you’re unable to digest it? Stress to the immune system and change in the gut microbiome composition which both contribute to intestinal permeability.

Corn growing in a field being shown as a food that causes leaky gut

6. Corn

This grain can contribute to leaky gut in a number of ways. To keep it simple, its good to know that corn is a crop that tends to be high in mold, often genetically modified and pesticide-ridden, and it has the closest molecular mimicry to gluten.

The high mold content can contribute to gut dysbiosis and the issue with molecular mimicry, as discussed above, is that it can cause the immune system to fire up, thus leading to fatigue and increased permeability in the gut lining.[8,9]

Two glasses of beer which contains alcohol and may contribute to leaky gut syndrome.

7. Alcohol

While substantial research has proven alcohol in moderation may improve health in the long run and the polyphenols in high-quality red wine may help reduce intestinal permeability, alcohol can exacerbate a leaky gut. Furthermore, chronic-excessive alcohol consumption leads to changes in the intestinal microbiota.[10, 11]

These changes include a decrease in the good microorganisms, an increase in harmful bacteria, and increased gastrointestinal tract inflammation, collectively causing increased intestinal permeability.

BUT, PLEASE DON’T FREAK OUT. You have options for survival.

While the best option is to steer clear of all alcohol for at least 60-90 days, especially beer, cider, and high-sugar alcohols (like wine or rum) while your gut heals, if you’re in a social setting or simply prefer not to give it up completely, there are a couple of good options. Tequila and vodka are the top choices. If you’re a whiskey drinker, I promise you that a little high-quality blanco tequila, which is very reasonably priced, will be a tasty change up. Honestly, it’s what I’ve done on several occasions.

If mixed drinks are your style, the best option is vodka, soda-water, and a twist of lime AKA a “Skinny b*tch” according to some bartenders.

8. Legumes

Legumes are a family of plants such as beans, peas, lentils, peanuts, that create the fruit they bear in pods. Inside those pods are the seeds we eat but its important to ask ourselves, biologically, what is the point of a seed?

The seed is the plant’s best effort to genetically survive and multiply. So, it’s meant to be hearty and survive harsh environments such as the digestive systems of humans and animals. To make them hearty, legumes, along with grains, are high in certain proteins called “lectins” as well as phytates and phytic acid. Because lectins, phytates, and phytic acid all make digestion difficult as they attempt to protect the seed, these proteins can be especially problematic for those with a leaky gut.[12]

While consuming legumes and other plants high in lectins, phytic acid, and phytates may be fine for many people, those with a leaky gut will often see an exacerbation of their symptoms. Remember, with a leaky gut, an impaired digestive environment often exists from decreased secretion of digestive enzymes and an imbalance in the gut bacteria. This together makes legumes, an already difficult food to digest unless prepared or cooked in very specific ways. Perhaps its time to strengthen your relationship with your crockpot or pressure cooker.

Bowl of quinoa- a leaky gut food to avoid because it is a pseudograin.

9. Pseudograins

There are several grains such as quinoa, amaranth, and buckwheat which do not contain gluten BUT, they have two issues:

Buckwheat and amaranth (along with oats) are commonly processed on the same machinery or alongside wheat, thus leading to gluten cross contamination.

Molecular mimicry is real. In other words, your body can confuse these foods for gluten since the molecular composition of their protein molecules closely mimics that of gluten when they’re broken down by the body. Because of this, if you have a sensitivity or allergy to gluten, or your immune system is simply on edge from a variety of things (exposure to mold, stress, heavy metals, etc.) then your body may easily become inflamed and confuse the pseudograin proteins for gluten. When this happens, inflammation via stress on the immune system may lead to increased intestinal permeability.

Summary and a Leaky Gut Diet Food List PDF

Need a reminder on the top leaky gut foods to avoid? Take a screenshot of the below image or use our link to the Leaky Gut Foods to Avoid PDF to save, print, download, or hang up an easy reminder of the foods you should most avoid to heal your gut and keep your gut healthy.

Do Certain Foods Make Leaky Gut Better?

Interested in learning about the BEST foods and our top tips and tripos to help heal your leaky gut? Check out our post on the 5 Best Foods for Healing a Leaky Gut and our Top 7 Tips to Heal the Gut Naturally to learn more. 

Also, if you’re looking to repair your gut after some trauma from stress, mold biotoxin illness, or other issues, be sure to check our our post on the best gut healing powders.


  1. Fassano, A., Flaherty, S. Gluten Freedom: The Nation’s Leading Expert Offers the Essential Guide to a Healthy, Gluten-Free Lifestyle. Wiley. 2014.
  13. Axe, J. Eat Dirt: Why Leaky Gut May Be the Root Cause of Your Health Problems and 5 Surprising Steps to Cure It. Harper Wave. 2016.