The index of nutritional quality (INQ) is a scoring system that rates foods by their nutrient density — the amount of beneficial nutrients delivered per calorie. A food’s INQ compares its content of protein, vitamins, and minerals against its energy: nutrient-rich, lower-calorie foods (vegetables, lean meats, dairy) score highly; energy-dense, nutrient-poor foods (sugary drinks, confectionery) score badly. Developed as a tool for nutrition education and food policy, it gives a single number to the intuitive idea that some calories carry more nourishment than others. Like all nutrient-profiling systems, it simplifies — no single score captures a whole diet — but as a quick comparator of foods’ nutritional value per bite, the INQ is genuinely useful.