Watercress is ranked as the most nutrient-dense vegetable by the Centers for Disease Control and Prevention, providing essential nutrients in a low-calorie package. Despite its nutritional benefits, watercress is rarely consumed, with familiar vegetables like broccoli and carrots taking precedence in home kitchens and restaurant menus. Research shows that increasing plant diversity in one's diet is more important than focusing on the healthiest single vegetable, as variety leads to improved gut microbiome diversity and reduced disease risk.

Most diets remain narrow, with people sticking to familiar, affordable, and easy-to-prepare vegetables, even if they are less nutrient-dense. Adding watercress to meals three to four times weekly can provide significant nutrition without adding many calories, making it a valuable addition to a healthy diet. Expanding vegetable variety supports fiber intake, micronutrient coverage, and long-term health more effectively than focusing on any single food item, emphasizing the importance of incorporating a wide range of plant foods into one's diet.