Most of us assume that memory loss and cognitive decline are just part of getting older. In this episode, a world-leading neurologist says that’s simply not true. That, far from being inevitable, Alzheimer’s and other neurodegenerative diseases result from decades of metabolic damage – which we have the power to prevent and even reverse.

I’m speaking with Dr David Perlmutter, a board-certified neurologist, six-time New York Times bestselling author, and one of the world’s leading experts on brain health. And in this fascinating conversation, we discuss the single biological mechanism that sits at the heart of virtually every neurodegenerative condition, from Alzheimer’s and Parkinson’s to long Covid and depression, and why understanding it changes everything about how you approach your lifestyle.

David’s key insight is that our brain’s own immune cells, called microglial cells, have the power to make or break our future brain health. Keep them in their protective state through diet, exercise, and metabolic testing, and we can safeguard our brain for life. Feed them with ultra-processed food and they will shift into a destructive state that drives neuroinflammation.

We discuss how, exactly, ultra-processed food damages the brain, why metabolic health is the key to cognitive longevity, and why the diagnosis of Alzheimer’s is really the end stage of a process that began decades earlier. The choices you make right now, in your 30s, 40s and 50s, are already shaping the brain you will have in your 70s and beyond.

If this all sounds science-heavy, rest assured David approaches it, just as he does in his new book, Brain Defenders, with clarity and plenty of practical takeaway. He outlines the specific blood biomarkers he believes everyone should be tracking, including fasting insulin, homocysteine and uric acid, for a remarkable window into your long-term brain health. We discuss why knowing your numbers is one of the most empowering steps you can take, how to go about getting tested, and how to act on what you find.

There is a great deal of fear around dementia, and understandably so. But what I hope you take from this episode is something David emphasises: we needn’t be scared because we have agency. The research is clear that lifestyle choices have a profound impact on your risk, and it is never too early, or too late, to start making them.

This is one of the most distinct and important conversations I’ve had about the future of your brain, and I think you will find it incredibly useful, thought-provoking and, above all, hopeful.