In the quiet corners of the American pantry, a small and overlooked fish has been accumulating a case for reconsideration. Sardines — cheap, shelf-stable, and nutritionally dense — offer omega-3s, vitamin D, calcium, and selenium in concentrations that rival far more celebrated foods. Yet the science of their benefit hinges not on the fish itself, but on a single, often-ignored act: how we handle what surrounds them in the tin. The distance between a meaningful nutritional choice and a merely adequate one, it turns out, is measured in the seconds it takes to drain a can.