Gut health scientist and dietitian Dr. Megan Rossi shares why diversity, not restriction, is the key to a thriving microbiome
What gut health myth do you wish people would stop believing?
One of the biggest myths is that you need expensive supplements, restrictive diets, or “detoxes” to have a healthy gut. In reality, your gut microbes thrive on diversity from everyday whole plant foods that are loaded with fiber — your microbes’ favorite fuel. Plus, getting the foundations right, like sleep, stress management, and movement, all help. Gut health isn’t about perfection or quick fixes; it’s about building sustainable habits that support your microbes over time.
If someone could only change one thing about their diet for better gut health, what would you recommend?
I’d encourage people to focus on adding more plant diversity to their week. Research shows that people who eat at least 30 different plant foods weekly tend to have a more diverse gut microbiome compared to those who only eat 10, which is linked to better overall health outcomes. Importantly, this isn’t just fruit and vegetables — legumes, wholegrains, nuts, and seeds plus herbs and spices all count, too. They’re what I call the Super Six.
Why is the gut so important beyond just digestion?
Around 70% of our immune cells live in the gut, and the gut microbiome communicates with almost every system and function in the body. So, it’s pretty much essential to whatever your health goal is, be it successful weight management, improved fitness levels, healthier skin, more resilient immunity, or even your happiness. It also has the power to influence how long you live and to protect you from over 70 chronic conditions and certain cancers.
What’s a simple daily habit that people can start today to improve their gut health?
A really simple habit is adding one extra plant food to your meals each day. That could be sprinkling mixed seeds onto breakfast, adding lentils to a pasta dish, or including an extra vegetable at dinner. Small, realistic changes are often the ones that make the biggest long-term difference because they’re sustainable. If you want recommendations that are more personal to you, check out my free quiz, “Is Your Gut Healthy?”
What do most people get wrong when they try to improve their gut health?
Many people become overly restrictive, cutting out entire food groups unnecessarily. While certain people may need tailored dietary support (for example, in the case of intolerances), for most individuals, diversity — not restriction — is the key to supporting gut health. Another common mistake is expecting overnight results. Your gut microbiome can respond surprisingly quickly to dietary changes, but meaningful, lasting benefits come from habits you can maintain consistently in the long term.
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