This Is Your Brain on Food

The most powerful part of the introduction is the author's own story. On holiday in Beverly Hills, Naidoo finds a lump in the breast and is diagnosed with cancer immediately after returning to Boston. Sixteen months of chemotherapy, surgery and radiation follow. Drinking turmeric tea before the first session, Naidoo decides: «I know how to cook, I know my body, so I can help myself with what I eat.» A smoothie of probiotic yoghurt, berries, kefir and dark chocolate comes along to every session, and Naidoo writes of never feeling nauseous. The story sets the book's tone: the author tried this advice first-hand.

Naidoo's path is interesting too. Raised in a large Indian family, the author felt cut off from home while training in psychiatry at Harvard and began cooking to cope with loneliness, later completing culinary school and a nutrition science programme and founding the first «nutritional and lifestyle psychiatry» programme in the US at Massachusetts General Hospital. Naidoo jokes about explaining the calories in half-litre sugary coffees to patients who blamed their antidepressants for weight gain.

Chapter 1 presents the gut-brain connection as a «romance». Gut and brain arise from the same cells in the embryo. The gut's own nervous system holds 100–500 million neurons, which is why it is called the «second brain». The vagus nerve links the two and signals travel in both directions. One of the book's most memorable facts: over 90% of serotonin receptors are in the gut. The microbiome helps produce dopamine, serotonin and GABA, so when the mix of gut bacteria shifts, mood can shift too.

The link also runs the other way. Naidoo cites research showing that just two hours of psychological stress can change the composition of gut bacteria. A tense family dinner or a traffic jam can disrupt the microbiome, and a disrupted microbiome in turn worsens mood. A 2019 study of over a thousand people found butyrate-producing bacteria associated with higher quality of life and certain bacteria missing in people with depression. These sections are clear and engaging, explaining complex biology with everyday examples.

The book's boldest point is a critique of psychiatry itself: diagnoses are lists of symptoms without biological markers, and doctors assume the problem lies only in the brain. Medical schools barely teach nutrition. Naidoo calls for a whole-body view. The book stays balanced, though: medication and psychotherapy are «miracles» for many patients, food is a supporting tool, and anyone with severe depression or suicidal thoughts must see a doctor.

The weakness is the strength of the evidence, and the book does not hide it. «How to Use This Book» admits that most evidence on the microbiome's effect on the brain comes from animal studies and that much of the research tested supplements rather than food. Even so, some chapter headings («turmeric», «rosemary», «fenugreek») sound more definitive than the evidence allows. One caveat: the book was written in 2020, and later research in some areas has reached more cautious conclusions.

• A candid, personal opening drawn from the author's experience of cancer
• Complex biology explained with everyday examples
• Concrete «eat this, avoid that» lists in every chapter, plus recipes