It had been a dark winter. Not early-sunset, cozy-sweater dark. I mean the black hole variety. I spent much of this December and January trapped in an emotional vortex, shuffling around in sweats (“athleisure” is too generous), crying at random, and snapping at my spouse. I baked cookies. I made pasta. Both helped, but only temporarily. In other words, I—like an outsize proportion of Americans—felt depressed.

On a frigid, blank-skied afternoon in mid-February, I forced myself on a walk. When I passed the local library, I noticed a book, This Is Your Brain on Food, in the window. The book was all about the connection between food and mood, written by nutritional psychiatrist and trained chef Uma Naidoo, M.D., who directs the Department of Nutritional and Lifestyle Psychiatry at Massachusetts General Hospital and serves on the faculty at Harvard Medical School. I headed inside, stepped up to the plexiglass-encased librarian, and borrowed the book.

In truth, the book confirmed what I already suspected: a carb-heavy diet was making me sad and sluggish. So, the next time I dragged myself to the supermarket, a wool beanie pulled low over my mess of hair, I filled my cart with color. I bought avocados, bright pink wild salmon, perky bunches of curly kale, walnuts, fat sweet potatoes, shiitake mushrooms, and fresh spinach. I splurged on seriously overpriced, out-of-season blackberries. I knew I’d make some good meals from my haul. But Dr. Naidoo had me thinking I might also find some happiness.

Many people benefit from medication and talk therapy, the most common interventions for mental health conditions like depression and anxiety. But the emerging field of nutritional psychiatry I’d been studiously reading about utilizes food and diet to improve mood and mental well-being. Multiple medical studies show that food plays a critical role not just in physical health but in mental and emotional health too. Nutritional psychiatry leverages the connection between healthy food and healthy minds, and offers real—and appetizing—help.

Meals like bright broiled salmon with super-garlicky spinach did make me feel noticeably better, physically and mentally. In my kitchen these days, lentils have replaced lasagna—and you’ll find more carrots than cookies. (Well, most of the time at least.) I’ve since returned my library book, but I know I’ll be bringing my new grocery lists into our post-pandemic world.

If you’re thinking nutritional psychiatry might be for you, here’s what you need to know:

First, what is nutritional psychiatry?

Working from the premise that what we eat impacts our mood, nutritional psychiatrists, unlike regular psychiatrists, incorporate food into their overall treatment plans. Nutritional psychiatry leans on certain nutrient-packed foods—those filled with vitamins, minerals, antioxidants, fiber, pro- and prebiotics, and protein—while cutting way back on nutritionally “empty” foods (sorry, sugar). These adjustments are designed to reduce brain inflammation, better regulate serotonin and dopamine, and influence a host of other mood-boosting reactions.

What does the brain have to do with our gut?

The brain connects to the gut through the vagus nerve. This “wandering nerve” acts as a two-way highway, constantly sending signals and chemicals back and forth between the brain and gut. One of these chemicals is serotonin, our natural mood regulator. We produce over 90 percent of our body’s serotonin outside the brain, in the gut—precisely where our food is digested and broken down into vitamins, minerals, and other nutrients. This enables a natural symbiosis between food and the body’s brain chemistry.

So, what should we eat to feel better?

Good mental health depends on a well-nourished brain. Doctors offer several main guideposts for building a diet that supports a healthy mood. Bear in mind, though, that “well-nourished” does not mean “perfect.” So don’t stress about eating that juicy cheeseburger or occasional bowl of pasta.