4 Gut Health Myths, Debunked – and What to Do Instead
The gut health conversation is louder than ever—but louder doesn't mean clearer.
Everywhere you turn, there's a new rule, a supplement to buy, or a list of foods to fear. But what's actually true when it comes to your gut? And what's just internet noise?
To sort it out, I sat down with Kate Scarlata, a Registered Dietitian and renowned gut health expert.
She broke down 4 common gut health myths—and shared what you can really do to feel better from the inside out.
Myth #1: Everyone needs probiotic supplements.
"The idea that everyone needs a probiotic is a big misconception," Kate explains. "Probiotic science is still in its infancy. While there are some probiotics showing specific benefits for certain symptoms or health conditions, a probiotic supplement is very specific to the individual and can place some people at health risk, such as those that are immunocompromised."
Myth #2: Fermented foods are always a source of probiotics.
"Fermented foods are often thought of as a source of probiotics, but that's not always the case," says Kate. "Probiotics are defined as specific strains of microbes that provide a demonstrated benefit to the human host. Most fermented foods, however, contain uncharacterized microbes that haven't been studied to determine their effects."
For example, when you make sauerkraut, the microbes in the cabbage come from the environment and are not strain-specific or proven to benefit gut health. While fermented foods can offer other health benefits, like increasing certain vitamins or making nutrients more bioavailable, they should not automatically be considered a reliable source of probiotics.
Myth #3: More fiber is always better.
"Fiber is often seen as universally beneficial, but it's not a one-size-fits-all solution," Kate explains. "Fiber is an umbrella term, and there are many different types with varying effects on the gut."
For example, short-chain fibers are rapidly fermentable and can produce a lot of gas, which might be uncomfortable for some people such as those living with irritable bowel syndrome, a common GI disorder. On the other hand, long-chain fibers tend to be fermented more slowly, often in the lower part of the colon, which is generally beneficial and better tolerated. However, tolerance to fiber is highly individual.
While fiber is important for gut health, over consuming it isn't always better. It's about finding the right types and amounts that work for your body.
Myth #4: Prebiotic tolerance isn't variable.
"People often think prebiotics are universally beneficial, but that does not appear to be the case," Kate emphasizes. "Prebiotics, like fructans found in onions and garlic, are health-promoting for many people, but not for everyone."
For example, individuals with IBS may experience symptoms like cramping or discomfort from consuming fructans, as these fibers may cause an imbalance in their gut flora, referred to as dysbiosis. Similarly, in a subset of people with inflammatory bowel disease (IBD), fructans have been shown to increase inflammatory markers, making them potentially less suitable.
While prebiotics can support gut health for many, they're not a blanket solution. It's important to listen to your body and recognize that what works for some may not work for others.
So What Can You Actually Do to Support Gut Health?
Kate shared a number of realistic, research-backed actions that almost anyone can take to support their gut health—no expensive supplements or extreme diets required.
Here's where to focus your energy:
1. Increase diversity of plant foods
Aim for 30+ different plant types per week (fruits, vegetables, legumes, nuts, seeds, herbs, spices).
"Diversity is key for feeding a wide range of gut microbes," Kate says.
2. Get enough sleep (7–9 hours/night)
Sleep isn't just for energy—it's essential for your microbiome.
"We know that sleep supports a more positive gut environment," Kate shares.
3. Manage Stress
"Stress has a significant impact on gut health," Kate explains. "When you're stressed, it can negatively impact the gut microbiome."
Managing stress through techniques like mindfulness, meditation, yoga, or exercise can help reduce these negative effects. Taking steps to support your mental well-being can directly benefit your gut health as well.
4. Engage in light exercise
Even gentle movement can support gut health.
"Gentle exercise brisk walking, yoga, hiking) helps increase microbial diversity," says Kate. You don't need an intense workout—just move regularly.
5. Avoid constant grazing
Let your gut rest between meals.
"There's something called the migrating motor complex—it's like the housekeeper of your gut. It only kicks in when you're fasting," Kate explains.
Constant snacking, even on small things like tea with milk, can prevent this gut-cleaning wave from activating.
6. Incorporate fermented foods
Even if they're not high in probiotics, fermented foods can still offer gut benefits.
"Fermentation can increase certain vitamins, like vitamin C, folate, and B12, and reduce phytates, which improves nutrient absorption," Kate highlights. Additionally, fermentation produces metabolites that can help regulate the immune system, making fermented foods a valuable addition to a gut-friendly diet.
7. Listen to Your Body
"Your body often gives you signals about how it reacts to certain foods," Kate explains. "Pay attention to those signals."
For example, if eating onions repeatedly causes crampy pain or discomfort that makes you need to lie down, it might be a sign that your gut isn't tolerating them well. However, even foods within the same category of fibers can be tolerated differently—what doesn't work for one person might be fine for someone else.
"For me, onions don't agree with my gut, but garlic, which is also a fructan, is totally fine," Kate shares. This highlights how individual tolerance varies and why it's important to adjust your diet based on your own body's responses rather than following general advice. Remember to stay curious with foods–as tolerance can change over time!
Kate Scarlata MPH, RDN is a Boston-based registered dietitian and New York Times best selling author with 30+ years of digestive health experience.
Want more from Kate? Check out The Gut Health Podcast or connect on Instagram.