At 51, I am often told I don’t look my age. At conferences, I have been mistaken for an intern. A few years ago, my son accompanied me to a school reunion, scanned my classmates, men the same age as me, and said, “Papa, they look like your grand uncles.” It was funny. It was also revealing. Because it feeds into a powerful illusion that aging is visible, controllable, even optimizable. That with enough discipline, we can engineer youth. That illusion is now a global industry. By some estimates, the longevity and anti-aging market is headed toward a multitrillion-dollar size over the next decade. In India, my home country, this is playing out alongside a different reality: 100 million people living with diabetes and a rapidly rising burden of cardiovascular disease. On paper, I fit the “fit” stereotype: a BMI of 21.5, vegan, reasonably fit, energetic through the day. That story is incomplete. A few years ago, I lost my mother.…