Protein explores the contemporary obsession with a nutritional superstar, tracing how protein moves through food systems and fitness cultures, strengthening some bodies and environments at the expense of others. Protein is everywhere—praised as a muscle builder, a weight-loss miracle, an anti-aging elixir, and the catch-all solution for everything from exercise recovery to global malnutrition. In Protein, Samantha King and Gavin Weedon argue that protein’s rise to nutritional superstardom has less to do with human dietary needs and more to do with how its indeterminate, adhesive qualities are marshalled towards commercial, scientific, and social imperatives. Tracing its path from nineteenth-century biochemistry to the status it enjoys today, they expose how protein has been marketed as a cure for global hunger, repackaged as an eco-friendly meat alternative, and wielded as a symbol of masculinity in the fitness industry. From whey waste in industrial farming to longevity drugs for aging bodies, Protein unpacks the myths behind the macronutrient and challenges what we think we know about food, health, and the forces that shape our diets.