Science has long counseled us toward whole grains, but a new study now offers something rarer than general wisdom: a specific number. Researchers have identified four to six daily servings as the threshold at which whole grains deliver their greatest protection against heart disease — a 'sweet spot' beyond which additional consumption yields diminishing returns. In a country where most people fall well short of even this modest target, the finding reframes an old nutritional truth as a precise, actionable opportunity to reduce the leading cause of American death.