How to Starve Bad Gut Bacteria to Better Your Gut Health

There are trillions of microorganisms in your gut, and research continually shows that bacterial diversity in the digestive tract is associated with better health outcomes, while a lack of biodiversity is associated with a number of diseases and dysfunctions. 

That said, if you know or suspect you’re experiencing gut dysbiosis (an imbalance between “good” and “bad” gut bacteria) due to autoimmune conditions, food poisoning, “leaky gut”, or an overgrowth of bacteria in your intestines, such as small intestinal bacterial overgrowth (SIBO), then starving out the bad bacteria and excess bacteria in general is an important step in treating your overall condition. 

Below, we’ll map out an action plan to starve bad gut bacteria, including dietary changes, sleep and exercise improvements, probiotic supplements, and, in some cases, antimicrobial or antibiotic therapy.

How to Starve Bad Gut Bacteria: Preparing Your Gut

The best way to get rid of bad bacteria is to follow a stepwise, foundation-up approach to making your digestive system more hospitable to good bacteria and less hospitable to bad bacteria in the long-term. In other words, killing off the bad bacteria with a prescription or herbal antibiotic may help in the short-term, but for long-term gut balance, a more holistic approach is needed. 

This isn’t to say that an antibiotic of some sort won’t be necessary or helpful. Research shows that probiotics can help support the body during antibiotic therapy, improving efficacy and reducing common side effects, including antibiotic-associated diarrhea 1 2 3. 

While it may seem like eating whole foods, exercising regularly, and improving sleep quality is generic, tired advice, there’s a reason these three lifestyle changes are so often recommended, and it’s not all about weight loss either. 

In the case of gut microbial balance, these key lifestyle changes are associated with greater biodiversity and improved gut health. In short, they go a long way toward correcting dysbiosis, even without a pharmaceutical intervention. 

Eat an Anti-Inflammatory Diet

As an example of how your diet affects your gut microbes, let’s talk about inflammation. Certain foods prevalent in the Western diet, like sugar, alcohol, and highly processed meats and carbs, are linked to high levels of inflammation 4. 

These foods can feed certain bacteria in your gut that contribute to inflammation and can lead to symptoms like bloating, gas, constipation, and irritable bowel syndrome (IBS), as well as damage to epithelial tissue that may result in “leaky gut.” When diet promotes an imbalance in the gut microbiome, this can increase pro-inflammatory activity and disrupt the gut barrier, creating a cycle of ongoing inflammation and damage 5.

Anti-inflammatory diets with the most research include: 

• Paleo diet
• Mediterranean diet
• Vegetarian diet
• Low-FODMAP diet 
• Low sucrose and starch diet (SSRD) 

These diets can improve the overall health of your intestinal microbiota while starving out bad bacteria. In the clinic, we have found that low FODMAP 6 and SSRD are generally the best options for those with SIBO or bacterial overgrowth. There is a good body of research supporting low FODMAP for IBS, which can overlap with SIBO 7 8. 

In more persistent or severe cases of bacterial overgrowth, like SIBO, a short-term elemental diet may be used under clinical supervision. 

This approach provides nutrients in their simplest, pre-digested form, allowing for rapid absorption in the upper small intestine and leaving little substrate available for bacterial fermentation. As a result, it can significantly reduce bacterial activity and improve symptoms. However, because an elemental diet can also impact beneficial microbes, it is typically used as a short-term strategy followed by a structured reintroduction phase to support long-term gut balance.

If you are interested in learning more about the elemental diet process, see our Elemental Diet Guide. 

Gut Healing Diets

FODMAP foods contain fiber in the form of short-chain carbohydrates (sugars) that the small intestine absorbs poorly. These sugars can feed unwanted bacteria. If those microorganisms are living in the wrong part of your intestinal tract, they may create digestive discomfort like bloating, diarrhea, and constipation. 

Avoiding FODMAPs or dramatically reducing them may starve out the bad gut bacteria over time, but cutting out FODMAPS forever isn’t the goal. Many FODMAP foods feed the good bacteria in your colon and are generally considered healthy to consume (such as broccoli, onions, apples, and garlic). The low FODMAP diet is meant as a temporary strategy to help solve gut dysbiosis as part of a broader approach. 

Eating foods rich in live bacteria is also great for lasting gut health. Fermented foods such as raw sauerkraut, kimchi, and kombucha can supplement good gut bacteria. However, fermented foods are often high in FODMAPs, so be cautious if you know you are sensitive to them.

When paired with the lifestyle shifts we’re about to discuss, quelling inflammation with a low-FODMAP diet is one of the best ways to starve bad gut bacteria.

Another promising option with emerging research is the low sucrose and starch diet (SSRD), which limits sugars and easily digestible carbohydrates that can fuel harmful gut bacteria and yeast. Reducing these key energy sources may help curb microbial overgrowth and the production of irritating byproducts, while supporting a more balanced gut environment where beneficial bacteria can thrive 9.

Research on an anti-inflammatory Mediterranean diet rich in fresh veggies and fruit, olive oil, whole grains, legumes, fresh meat, and fish, shows an association with supporting a balanced gut microbiome, which fortifies the intestinal barrier 10.

The Paleo diet may support gut health by removing processed foods and common dietary triggers. By emphasizing whole, nutrient-dense foods, Paleo-style eating has been shown to reduce markers of inflammation and improve gut symptoms in some individuals 11.

Plant-focused diets, namely vegetarianism, are consistently linked to beneficial changes in gut bacteria. Diets high in plant-based fiber can increase microbial diversity and support the growth of beneficial bacteria that promote gut health 12.

Exercise and Sleep to Support Your Gut

Exercise and sleep both support digestive health and help reduce bad bacteria. A systematic review of 10 studies found that active individuals, especially athletes, exhibit beneficial shifts in the gut microbiota compared with sedentary individuals 13. 

In another systematic review, researchers found that increased physical activity or fitness was positively correlated with higher bacterial diversity and greater abundance of certain phyla and short-chain fatty acids (which feed certain beneficial bacteria, including those listed above) 14. 

While the link between better sleep and microbial diversity in the gut is still in its early phases, we do know that quality sleep:

• Supports your immune system
• Supports mental health and wellness 
• Aids in decision-making  
• Helps in the body’s ability to turn over cells, heal, regenerate, and rejuvenate
• Supports you in making better choices around food and exercise

Our clinical work has shown that sleep and stress management are key to supporting gut health, and we consistently recommend strategies to improve them.

Probiotics and Prebiotics

Along with the lifestyle and dietary changes we’ve covered, probiotics are among the first lines of defense for maintaining or improving gut health. Research shows that probiotics can help support a balanced gut microbiome, improve digestion, and reduce common symptoms like bloating and constipation, all of which are important, since poor gut motility is a key contributor to dysbiosis and conditions like SIBO.

Preparing your gut with lifestyle changes and probiotics can help reduce or prevent the side effects of antimicrobials or antibiotics (which we’ll cover next), and in some cases, can be enough to eliminate the need to use a drug or herb like this in the first place 15 16 17. If you do need antibiotics, probiotics can be taken alongside them (spaced a few hours apart) to help reduce side effects and support gut health.

Furthermore, if antibacterial measures are needed, there’s evidence to suggest that probiotics actually increase their effectiveness 1 2.

We recommend a triple-therapy approach to supplementing probiotics, covering the three main categories of microbes that are living in your gut:

• Category one: Species in the genera Lactobacillus and Bifidobacterium 
• Category two: A fungal probiotic called Saccharomyces boullardi
• Category three: Soil-based probiotics 

In our clinical work, we’ve observed that this approach seems to be more conducive to balance and healing in the microbiota and the gut than a single category alone.

Prebiotics, another helpful dietary addition, are non-digestible fibers that selectively fuel beneficial gut bacteria, helping them outcompete less desirable microbes. As these bacteria ferment prebiotics, they produce short-chain fatty acids that support gut health and create conditions that can inhibit the growth of pathogenic species 18. If you are following a low FODMAP plan, make sure you are consuming the appropriate type of prebiotics.

Antibiotics and Antimicrobials

Antimicrobials and antibiotics, whether pharmaceutical or natural, may help to get rid of bad bacteria, but are more effective when your foundations are in place. The foundations we’ve already covered are diet, exercise, probiotics, and sleep. Importantly, these key steps should all be in place as the foundation before you introduce antibiotics or antimicrobials. 

These medications and/or herbs are designed to kill pathogens and other harmful microbes. However, overuse may do some damage, such as reducing microbial diversity or increasing the risk of heart disease, in the process 19 20 21 22.

This isn’t to say that these drugs and herbs don’t have their place in medicine or gut health, but it is to say that they’re most effective when used after all other interventions have been put in place, and after you’ve prepared your gut for them.

FAQs

How do I know if I have an imbalanced gut microbiome?

Common signs include bloating, gas, diarrhea or constipation, food intolerances, and fatigue. In some cases, conditions like irritable bowel syndrome or small intestinal bacterial overgrowth may be linked to microbial imbalance, though symptoms can overlap with other conditions.

Are there foods that can reduce harmful gut bacteria?

It’s less about specific foods and more about overall eating behavior. Certain dietary patterns can limit the fuel available to less beneficial microbes. Diets lower in simple sugars and highly fermentable carbohydrates (like the low FODMAP diet or the SSRD diet) may help curb their growth, while regularly eating fiber-rich whole foods supports beneficial bacteria and a more balanced gut environment.

Can a low FODMAP diet help with gut bacterial imbalance?

A low FODMAP diet can help reduce symptoms by limiting fermentable carbohydrates that feed gas-producing bacteria, especially in IBS or SIBO. However, it’s not intended long-term, as many FODMAP foods also nourish beneficial microbes. Reintroduction is key to restoring balance.

How do you balance good and bad gut bacteria?

Gut balance is supported through diet and lifestyle: eating a diverse, fiber-rich diet, including fermented foods and probiotics, staying active, managing stress, and getting quality sleep. These factors help beneficial microbes thrive and maintain a stable ecosystem.

Are probiotics beneficial for gut health?

Probiotics can help restore balance, particularly after disruptions like antibiotics or infection. Certain strains, including Lactobacillus and Saccharomyces boulardii, have been well-researched to support gut health, though their effects can vary by individual.

What are the best ways to support a healthy gut microbiome?

A varied, minimally processed diet rich in fiber, along with regular exercise, good sleep, and stress management, are among the most effective ways to support microbial diversity and long-term gut health.

Does fasting improve gut microbiome balance?

Fasting may temporarily reduce nutrient availability for gut microbes, but there is limited evidence that it selectively improves microbial balance. Long-term dietary patterns have a much greater impact on gut health.

Do I need to completely cut out sugar for better gut health?

No. Complete elimination isn’t necessary. However, reducing excess added sugars and highly processed carbohydrates can help support a healthier microbial balance when combined with a nutrient-dense diet.

Do fermented foods actually improve gut health?

Fermented foods like yogurt, kimchi, and sauerkraut contain live microbes that may support gut diversity and function. Regular consumption has been associated with improved microbial diversity and reduced inflammation in some studies.

How long does it take to improve gut microbiome balance?

Changes in the gut microbiome can begin within days of dietary shifts, but meaningful, stable improvements typically take weeks to months. Long-term consistency in diet and lifestyle is key to maintaining those changes.

Maintaining Gut Health After Starving Bad Bacteria

The goal in learning how to starve bad gut bacteria is long-term bacterial balance. A healthy gut microbiome supports a healthy gut lining, leading to less inflammation and fewer health issues associated with a leaky gut or other forms of gut dysbiosis. These are all good things to support your overall health and wellbeing.

While you can’t micromanage an ecosystem, you can create an environment that encourages what you want (healthy bacteria) and discourages what you don’t want (unhealthy bacteria) through diet, lifestyle, and probiotic supplements. Preparing your gut to handle antimicrobials is key, but maintaining these changes to support a healthy gastrointestinal system long-term is the best strategy for starving bad gut bacteria.

If you need some guidance figuring out where to start, we’re here to help. Learn more about how to become a patient with us, and let’s get started.

Dr. Michael Ruscio is a DC, natural health provider, researcher, and clinician. He serves as an Adjunct Professor at the University of Bridgeport and has published numerous papers in scientific journals as well as the book Healthy Gut, Healthy You. He also founded the Ruscio Institute of Functional Health, where he helps patients with a wide range of GI conditions and serves as the Head of Research.