Seven months ago, I was a recent transplant to Mexico, where I moved to focus on my travel writing and, of course, to eat all the foods. I arrived, healthy, in early September and promptly made cruising for street food a central part of my daily routine. On any given day, I might breakfast on chorizo tacos at the bustling covered market across the street from my apartment; wander down to the center of town for a deep bowl of porky pozole, or hominy stew, for lunch; and, for dinner, munch on a giant wood-fired tlayuda, a sort of Mexican pizza constructed atop a crispy corn tortilla the size of a platter. Though my eating habits sound indulgent, I was researching and writing about these wonderful traditional foods in addition to greedily to scarfing them down for my own satisfaction. In fact, I had finally found the union between my personal interests and my professional career that I had been seeking, for years, as a freelance writer.

But a few weeks ago, seated around the Passover table with my extended family of atheist New York Jews, my sad, mostly empty plate was more macrobiotic Gwyneth Paltrow than it was gluttonous Guy Fieri. As loaded dishes of food made their way past my hungry eyes, I mentally ticked off what I couldn’t eat: the brisket, made with tomato paste, a nightshade; the hummus, made with chickpeas, a legume; the bread of affliction itself, the matzoh, made with wheat, and thus that malevolent gluten.

For most people, the holidays are a time of excess, an occasion to gather around the table with family and friends and go to town, imperial Roman-style, on as much food and drink as is possible to stuff down one’s gullet in a two-hour timespan. A food writer, recipe developer, and obsessive eater, I’m typically the Nero at such events, consuming plate after plate in a manner so decadent it would be sure to impress the depraved first-century emperor so dedicated to victuals that his Golden Palace featured a circular banquet hall that rotated day and night.

You know that old cliché “and then, overnight, everything changed”? Well, that’s essentially what happened to me. In late October, just two months after my arrival in Mexico, I acquired a urinary tract infection, identical in nature to the dozens I’ve contracted in my life. I went to the pharmacy, asked for the antibiotic I always use to treat them, and soon felt better. But five days after finishing the course of medication, I awoke to find that my entire body was itching and burning without cease. Day by day, as the uncomfortable sensations increased in intensity, interrupting my sleep and driving me insane, I looked for a logical explanation—failing to link the problem to my recent antibiotic usage.

It was worse than I thought: Almost everything I ate affected my skin and nerves, and certain common allergens like alcohol, dairy, and, yes, much-maligned gluten made my issues much, much worse.

Was it the laundry detergent I switched to when I moved? I washed all my bedding and every article of clothing in new, additive-free detergent. Was it an environmental allergen, a blooming plant native to my new home? I starting popping Claritin like candy.

Absolutely nothing helped—until a sage friend suggested I start keeping a food journal to see if anything I was eating made my symptoms worse. At first, I scoffed at the idea—did she know who she was talking to? The food writer with the iron stomach who could down a bowl of habañero-laced tripe soup without so much as a burp afterward, the gourmand who secretly rolled my eyes at family and friends who claimed to have “gluten intolerance” or a “dairy sensitivity”?

But with my options running out—and my chronic itching morphing into a troubling pins-and-needles neuropathy—I acquiesced. I was soon able to see that the problem was, in fact, linked to my diet. And it was worse than I thought: Almost everything I ate affected my skin and nerves, and certain common allergens like alcohol, dairy, and, yes, much-maligned gluten made my issues much, much worse. Depressed and overwhelmed by the idea of figuring out any kind of “elimination diet” on my own—and still having no earthly idea that the whole nightmare had been kicked off by those antibiotics I had taken—I trekked back to my native New York City in mid-December, working with a naturopathic doctor to formulate a plan to regain my health.