In Ketones: The Fourth Fuel, science writer Travis Christofferson weaves a fascinating narrative of humanity's quest to understand how our bodies produce energy - transporting us on a scientific expedition from the past to the present - across early modern Europe to modern laboratories spanning the globe.

The listener is taken on a riveting and revelatory journey that follows Nobel Prize-winning scientists from the 19th and 20th centuries as they map the pathways and cycles that comprise human metabolism. The listener is left with a new and lasting appreciation for the silent chemical motion that keeps us alive and healthy. Ultimately, the narrative arrives at a remarkable discovery that rewrites everything we thought we knew about metabolism - with profound therapeutic consequences.

Coming back to the present, Christofferson reminds us that Americans are sicker than they have ever been. Heart disease, cancer, dementia, obesity and type 2 diabetes are rapidly becoming the norm. Yet, we are presented with a revelation: the realization that we all have a potent, easy-to-access hybrid metabolism that generates a different fuel - the fourth fuel - that “supercharges” our metabolism in a way that slows aging and bypasses the metabolic dysfunction that leads to the multitude of diseases that plague modern society.