Starbucks has declared itself all in on protein. Beginning this month, customers can order Protein Lattes and Protein Matchas, or add Protein Cold Foam to their cold brews and Frappuccinos, turning a daily caffeine ritual into something resembling a workout supplement. This isn't simply about menu items. It signals how deeply the protein craze has embedded itself into American culture. Across the grocery aisle, protein has become the nutrient of the moment, highlighted with the same zeal once reserved for fat-free labels.