You Are What You Eat—And Who You Hang Out With

Most of us have heard the phrase, “You are the average of the five people you spend the most time with.” It’s a compelling idea, often applied to our behaviors, work ethic, or attitudes. But what if I told you that this concept might run deeper—down to your biology? Groundbreaking research into gut microbiomes suggests the people we surround ourselves with may shape not just who we are emotionally or mentally, but also on a cellular level.

Digestive Drama and the Rise of Microbiome Science

The last decade has seen an explosion in microbiome research. Publications on this topic have jumped from under 400 in 2013 to over 25,000 today—a fiftyfold increase. This isn’t just curiosity; it reflects the mounting importance of the microbiome’s influence on human health. One reason for this surge is the growing prevalence of digestive disorders. Between 1990 and 2019, gut disorders increased by nearly 68%, contributing to over 2.5 million deaths globally.¹ Alarmingly, about 40% of Americans report significant disruptions to their daily lives caused by digestive issues.²

At the heart of this “digestive drama” lies the gut microbiome—an intricate ecosystem of trillions of microbes residing in your digestive tract. While many specific gut health issues require medical supervision, research provides some guiding principles for improving microbial health:

• Microbial diversity is key—it’s not about good vs. bad bacteria but having a diverse community.
• Probiotics vs. Prebiotics—Probiotics are the microbes themselves; prebiotics are the foods that fuel them.
• Diets rich in variety—Eat plenty of fiber-rich, whole foods to naturally support microbial diversity.
• Raw fermented foods—These, such as kimchi, yogurt, and sauerkraut, are more effective than most probiotic supplements.

It turns out that what we eat—and how much variety we introduce into our diets—lays the foundation for better gut health and, by extension, improved overall health.

Kissing and Microbial Swaps

We’ve all been through times when illness sweeps through a family or work group like wildfire. Thanks to COVID-19, we became acutely aware of the ways germs spread by breathing the same air or touching shared objects. But what about the not-so-obvious microbial exchanges?

The average 10-second kiss swaps around 80 million bacteria between partners—yes, 80 million. While this might sound like a surefire way to spread illness, emerging evidence paints a more nuanced picture. When one partner has a healthy gut microbiome—cultivated through a diet of fiber-rich whole foods—kissing can actually transfer those beneficial microbes to the other. This microbial “gift” helps diversify the other person’s gut microbiome, potentially contributing to better health.

However, this works both ways. If your own habits have left your microbiome imbalanced, consider what you might be sharing. When we rethink kissing as more than an emotional exchange, it becomes a powerful act of physical sharing, akin to offering—or borrowing—an asset of health. Ask yourself, “Is my microbiome something I’d want to share?”

You Are What Your Friends Eat

The microbial swapping doesn’t stop at intimate partners. A fascinating study by Bedhini et al. highlights how even distant social connections influence the microbiomes of those in their circle.³ Friends, colleagues, and even friends of friends significantly impact each other’s gut microbes through shared meals, environments, and habits.

It’s a powerful reminder of how biologically interconnected our lives are. Make no mistake—our lifestyle choices remain the primary drivers of our health. What you eat and do impacts which microbial populations thrive or wane in your gut. However, the strains of microbes you’re exposed to through social interactions are a meaningful ‘secondary input.’ When you frequently share meals with people prioritizing plant-heavy, fiber-rich diets, your exposure to beneficial strains increases. Conversely, you may absorb less desirable microbes if those around you indulge in poor dietary habits.

Rethinking Community and Health

The idea of being selective about who you spend time with based on their microbiomes may initially sound extreme. But rather than avoiding people with less-than-ideal habits, we should aim to encourage communal, health-oriented practices. Imagine families or communities committing collectively to healthy, gut-friendly routines:

• Meal-sharing initiatives—Hosting potlucks centered on diverse, plant-rich dishes.
• Time in nature—Engaging in outdoor activities that promote exposure to beneficial soil microbes.
• Minimized antibiotic reliance—Only undergoing antibiotic treatments when absolutely necessary to protect gut diversity.
• Education and cooperation—Sharing knowledge about microbiome health to inspire change across social networks.

Such collective efforts amplify individual health benefits across groups, whether within a family, workplace, or neighborhood.

Health as a Shared Mission

These findings on microbial exchange offer an inspiring new lens for viewing health. We are not just isolated individuals trying to “win” at maintaining wellness. Instead, humans form deeply interconnected biological ecosystems influenced by our relationships and environments.

Our gut health is less about one-off actions and more about collaboration—creating routines, communities, and shared practices that mutually elevate those involved. Whether you’re cooking a healthy meal with a friend, swapping sourdough starters with a neighbor, or committing to a workout group, these shared efforts reinforce not just emotional bonds but biological resilience too.

The age-old adage “you are the average of the five people you spend time with” suddenly has very complex, scientific backing. Who you socialize with can determine which microbial strains you’re exposed to, the diversity of your gut microbiome, and, ultimately, your health. And just like shared laughter or meals, the microbes you swap might be influencing those closest to you.

Your Next Step Toward Connection and Growth

Want to harness this science to level up your relationships—and life? Start paying attention to your social circles’ habits while refining your own. Encourage gut-healthy practices in your family, among friends, or even with your colleagues. After all, cultivating a healthier you often begins with fostering a healthier ‘we.’

For deeper insights into the interplay between biology, behavior, and health, check out The Energetic Investor. Make choices that feed not just your biology but your mind and connections as well. Because, truly, we are what we eat—and who we hang out with.

References

1. Wang, R., Li, Z., Liu, S., & Zhang, D. (2023). Global, regional, and national burden of 10 digestive diseases in 204 countries and territories from 1990 to 2019. Frontiers in public health, 11, 1061453. https://doi.org/10.3389/fpubh.2023.1061453
2. Reed, C. New survey finds forty percent of Americans’ daily lives are disrupted by digestive troubles. American Gastroenterological Association https://gastro.org/press-releases/new-survey-finds-forty-percent-of-americans-daily-lives-are-disrupted-by-digestive-troubles/ (2022).
3. Beghini, F., Pullman, J., Alexander, M. et al. Gut microbiome strain-sharing within isolated village social networks. Nature 637, 167–175 (2025). https://doi.org/10.1038/s41586-024-08222-1