Walk into any conversation about health in urban India, and you’ll hear the usual suspects blamed for rising rates of diabetes, obesity, and digestive problems: processed foods, sedentary jobs, and stress. The trillions of microbes that live in the gut are rarely mentioned, yet doctors increasingly believe that this invisible ecosystem is changing faster, and more unevenly, than most people appreciate.
There’s a common assumption that moving to a city simply “depletes” your gut bacteria, as if urban living flattens everyone’s microbiome into the same Western pattern. The reality emerging from recent research is much more interesting, and frankly more useful, than that.
This fact was clearly demonstrated earlier this year in one of the largest microbiome studies ever conducted in South Asia. The researchers sequenced gut bacteria from 575 adults across ten culturally and geographically distinct communities in India and Sri Lanka — from the Spitians in the Himalayas, to the Gond, Kollam, and Koya communities in central India, to the Naga groups in the northeast — and compared rural and urban members of each.
The study aims to determine whether changes in the gut microbiome that accompany urbanization follow one global pattern or take different paths across populations. The answer, doctors say, is the part worth paying attention to: Urbanization does drive change, but through several distinct pathways rather than one unified pathway, where geography and community identity explain more variation than just living in a city or village.
This is where the popular narrative collapses. It is tempting to think of urbanization as a single force that flattens India’s internal diversity into a single, Western-style homogeneous image. But a Naga family adapting to city life in Kohima does not undergo the same microbial shift as a family moving to Delhi from rural Rajasthan. Diet, culinary practices, water sources, and even altitude all leave a distinct imprint that urban life simply cannot erase.
However, there are certain patterns that recur. Low fiber intake, increase in processed and packaged foods, lack of physical activity, variable sleep schedules, and increased use of antibiotics are consistently associated with decreased microbial diversity in urban populations, both in India and globally. The loss of diversity is of clinical importance, as a less diverse gut microbiome has been linked to poor immune regulation, increased inflammatory activity, and increased long-term risk of metabolic diseases, such as type 2 diabetes, which is rising sharply throughout urban India.
What surprises most patients is the timeline. This is not change that unfolds across generations. Microbial shifts linked to diet and environment can begin within months of a lifestyle change – a new job with irregular meals, moving from a shared family kitchen to on-demand, a course of antibiotics to treat a minor infection. People notice bloating or fatigue long before they associate it with what’s going on in their gut.
The truth is that urbanization is not destiny – the same research shows that meaningful diversity can be maintained even in city dwellers who maintain traditional dietary patterns. There is not a single “Indian intestine” that can be protected; The country’s microbial diversity is itself extraordinarily diverse, and urban health advice imported wholesale from Western studies may not agree precisely with it.
High-fiber, low-processed, regionally rooted diets aren’t just cultural preferences — they may be more beneficial for gut health than most people realize. Urban life has not destroyed India’s gut bacteria but is quietly rewriting it, community by community, class by class.
The author is Director – Gastroenterology, CK Birla Hospital, Gurgaon.
The opinions expressed in this article are those of the author and are not intended to reflect the opinions or views of The Week.
