There came a point just a few months ago when I felt I was on the brink of gastrointestinal ruin.
As an interim restaurant critic for The New York Times, I had eaten dinner at a restaurant every night for three straight weeks. I felt fine. Yet I’d wake in the middle of the night thinking about all the sugar I’d just ingested, or the steak I’d polished off, distressed over what all this eating was doing to my body — and specifically, what it was doing to my gut.
I am obsessed with gut health. I grew up in a family that talked openly about digestion. My father couldn’t live without his daily cocktail of milk and psyllium husks. We believed that gut health was key to our overall well-being.
The American public has come to a similar conclusion. Supermarket shelves are lined with prebiotic sodas, probiotic supplements and fiber-rich cookies and bars. Influencers discuss their irritable bowel syndrome openly on TikTok.
And today there are services that can analyze a stool sample and tell you what kind of bacteria populate your gut. So I embarked on a two-month experiment on that microbiome to chart the effects of all of those restaurant meals on my gastrointestinal health.
The results surprised me. I also learned that when it comes to the gut, few things are black-and-white.
I enlisted the help of two Stanford University scientists who run one of the leading microbiome laboratories in the United States: Justin Sonnenburg, a professor of microbiology and immunology, and his wife, Erica Sonnenburg, a senior research scientist in microbiology and immunology.
With the Sonnenburgs’ guidance, I chose Zoe, a personalized nutrition app, to do the testing, because it’s popular and comprehensive. (For $294, you get testing kits for your gut health, blood sugar and blood fat.)
The Sonnenburgs divided the experiment into three stages: one in which I ate out for every meal and drank alcohol freely, a second in which I ate only at home and didn’t drink, and a third in which I mixed dining out, eating at home and drinking. Each phase lasted two weeks — the longest stretch I could manage given my job, and the shortest in which the Sonnenburgs thought they would detect changes. After each one, I sent a stool sample to Zoe, which then sent data on my gut composition to the Sonnenburgs.
My meals during the two weeks of dining indulgence varied wildly — I visited Lanzhou beef noodle soup shops, ate lamb stew at a French bistro, sampled chile cheese toast at a North Indian restaurant and spent all night eating in a diner. My at-home stint conveniently aligned with a stay at my parents’ house, where the meals looked like those I grew up with: khichdi, dal and okra sabzi for dinner, leftovers for lunch and oats for breakfast.
Before the third phase — a mix of home and restaurant meals — the Sonnenburgs gave me guidelines to follow, based on their studies of foods that yield healthier guts: Eat less meat and more plants. Fermented foods like yogurt and kimchi are a must, they said. They didn’t have conclusive thoughts on alcohol consumption, but they advised me that when drinking, to do it in moderation. It was the kind of advice you’d expect to hear from any nutritionist.
I thought I’d feel drastically different during each phase, as my diet was changing so much. I didn’t. (This should have been my first clue about the results.)
To interpret the data, the Sonnenburgs focused on two types of bacteria whose presence microbiologists consider to be consistent with a healthy gut and that made up a large proportion of my microbiome: Bifidobacterium longum and Faecalibacterium prausnitzii.
Bifidobacterium followed the pattern they expected: most abundant when I was eating at home, slightly less so when I mixed eating at home with eating out, and least abundant when I was exclusively eating out.
My levels of Faecalibacterium prausnitzii, though, didn’t change meaningfully, which aligned with a broader observation: The ratios of all bacteria in my gut stayed relatively consistent throughout the three phases — a sign that I have a stable microbiome.
The Sonnenburgs attributed that finding in part to how I grew up — eating mostly Indian vegetarian food — as studies have shown that people with plant-based diets have healthier guts.
“How you have eaten for the majority of your life has a huge impact on the species that are there,” said Dr. Erica Sonnenburg. “If you were to tell me you grew up with a McDonald’s diet,” she added, “I would be floored looking at your microbiome.”
I was feeling encouraged — smug, even. And then I got an email from Zoe.
“Overall, scores are poor,” began the analysis from Dr. Tim Spector, an epidemiologist who co-founded Zoe. For each phase of the experiment, my gut microbiome diversity scored well below what Zoe considers to be optimal.
In judging gut health, Zoe takes a different approach from the Stanford scientists. Based on its own studies, it tests for 100 microbes it associates with positive and negative health outcomes — 50 of each. Of those 100, Faecalibacterium prausnitzii is included (as a positive marker) but not Bifidobacterium longum. Zoe concluded that I had far more negative than positive microbes, and reported that this makeup didn’t change much over the three periods.
“It means you are feeding your bad bugs” when eating foods like bread and sugary desserts, Dr. Spector said. “You want to be feeding your good bugs to weed out the bad ones” by adding fermented foods and fiber-rich ingredients like nuts and seeds.
But the lack of change was possibly a good sign, he said. “You are getting lots of diversity in your diet, whether home cooking or restaurant eating,” which meant that even with all those bad microbes, my gut was resilient to temporary shifts in diet, he said.
Dr. Justin Sonnenburg was somewhat dubious about the Zoe results. He said several bacteria species the company tracks in its analysis have not been well studied, he said, and tend not to be abundant in the gut microbiome. (In response, Zoe said its research “is grounded in the world’s largest in-depth nutrition and gut microbiome database.”)
The Sonnenburgs also cautioned that the company is trying to sell customers on an app and supplements, so it has a vested interest in telling customers there’s room for improvement. (At the end of a phone call, Dr. Spector encouraged me to purchase Zoe’s prebiotic mix and offered a sample.)
The Stanford scientists even had caveats to their own analysis: I was just one subject, studied over a relatively short period, so I should take the results with a grain of salt.
Guts are like snowflakes. “Everyone’s microbiome is so unique,” Dr. Erica Sonnenburg said. “The bacteria causing you problems may not cause the same problems in me because I have this other five bacteria.”
My microbiome is probably not in immediate danger. But I came away with a few strategies for being more gut-conscious as a frequent restaurant-goer.
First, make the most of your at-home meals by incorporating plenty of plants and fiber. When eating out, try to order a balanced meal with a diverse array of ingredients. Approach gut-testing services with skepticism. A healthy diet in the long-term can help you handle short-term disruptions.
And above all, trust your gut.
“We get emails all the time that say, ‘This is my microbiome report, what do you think?’” Dr. Erica Sonnenburg said. “And the first thing I ask is: How are you feeling?”
“If you feel fine, that is what is most important.”
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Priya Krishna is a reporter in the Food section of The Times.
The post What Has All This Restaurant Food Done to My Gut? appeared first on New York Times.
