Stephan J. Guyenet, PhD, is a prominent neuroscientist and obesity researcher with a PhD in neuroscience from the University of Washington. He’s the author of The Hungry Brain and the founder/director of Red Pen Reviews, a platform dedicated to delivering clear, balanced, and thorough analyses of health and nutrition books. As a research fellow at the University of California, San Francisco, and a frequent public speaker and educator, Guyenet focuses on how the brain regulates body weight and appetite—especially through mechanisms like the “lipostat” and hormones such as leptin—and advocates evidence-based, brain-centered approaches to combat obesity and improve diet-related health.