That December of 2017, escalating into mania, Matt had left home, cut off contact, and wandered the streets, eventually taking a bus from the Bay Area to Southern California. From his increasingly alarming Snapchat and Instagram posts, we knew he had no money, and that he’d slept one night behind a dumpster and another in a lifeguard tower. As dawn broke that Friday morning, his social media channels had gone silent and his three sisters hadn’t heard from him in 18 hours.

Matt’s struggle was not uncommon. Nearly a quarter of American adults now take psychiatric medications, and adolescents are in crisis. Doctors broadly agree that current treatments are inadequate and often lead to intolerable side effects, and adults with severe mental illness die on average 10 to 20 years earlier than the general population.

Matt is alive and thriving today, but our family’s harrowing five-year journey proved that medication and therapy alone couldn’t make him better. We had to push back hard on experts who said bipolar disorder was a chemical imbalance that couldn’t be healed with diet. Preliminary research is proving those doctors wrong, and more people deserve to know this.

My husband and I are philanthropists from Silicon Valley, a region built on faith that innovation can solve the most intractable problems. But like millions of other parents of children diagnosed with a mental illness, we had come to feel helpless. With all our knowledge and resources, we had not even managed to keep our son safe.

On that terrifying morning, I tried to woo Matt back with food. After dragging myself off the floor, I sent him an email from an account I knew he hadn’t yet blocked, asking if he might like restaurant gift cards for Christmas. He responded right away: “McDonald’s starbucks subway burger king!!” The door opened to more communication, and my husband was able to retrieve Matt at a Starbucks the next day, leading to a fourth hospitalization.

After that, Matt stayed on his medications and did everything he could to get well. He was treated by 41 clinicians and prescribed 29 meds before his psychiatrist pronounced his illness treatment resistant. Luckily, that’s when I met the host of a mental health podcast who had gone on a ketogenic diet — low in carbohydrates, high in fat and moderate in protein — to treat his medication-induced weight gain, only to find that his lifelong bipolar symptoms resolved.

Through research, I learned the story was not unique. I found increasing evidence pointing to the promise of keto for treating a range of brain-based disorders, not only bipolar disorder but depression, schizophrenia, Alzheimer’s disease and autism. The strongest evidence that keto can help the brain comes from clinical trials in epilepsy dating back 100 years, demonstrating reduction or even elimination of seizures.

Any dietary approach that restricts carbohydrates can induce nutritional ketosis. That includes Atkins-like diets based on animal protein, but also intermittent fasting and versions of Mediterranean, vegetarian and, with the right supplements, vegan diets. When dietary carbohydrates are limited, the body produces ketones as an alternative fuel source. Published studies show that ketosis stabilizes brain networks and also reduces inflammation.

Ketogenic diets remain controversial, and the internet is rife with claims warning of long-term damage to health. But countervailing evidence is accumulating in cardiovascular disease, Type 2 Diabetes, kidney disease and cancer.

A “metabolic” approach to mental disorders is catching on at leading institutions. Stanford University established a “Metabolic Psychiatry” clinic in 2015, founded by Dr. Shebani Sethi, who recently led a 4-month clinical trial of ketogenic diet for serious mental illness. Preliminary results show remission of psychiatric illness in 80% of those who adhered to the diet, as well as reversal of metabolic syndrome in 100%. Additional trials are under way, with a recent French cohort showing weight loss and psychiatric symptom improvement in all patients, with nearly half no longer meeting criteria for mental illness after treatment.

In January 2021, after nearly five years of battling bipolar illness, Matt started a ketogenic diet under the guidance of Dr. Chris Palmer, a Harvard-trained psychiatrist. That spring, Matt needed only quarter of the dose of medication he’d needed the year before to fend off mania. Within four months, his mood was stable, and his intellectual vitality had returned. He graduated from college and now works full-time in tech, produces electronic music, and is back to top form in weightlifting, chess and piano. He continues to slowly taper his medications, with no signs of the mania or depression — or even anxiety, insomnia, or brain fog — that plagued him for five years.

Nutritional ketosis may not work for everyone, but doctors and families deserve credible information about a dietary intervention that could, at the very least, beneficially complement existing psychiatric treatments. Prescription pharmaceuticals are commonplace and widely accepted by patients, physicians and insurers. A dietary prescription should also be on the table.