Answer:
A measure of the nutrients a food provides relative to the energy it provides; the more nutrients and the fewer kcalories, the higher the nutrient density.
Nutrient density identifies the amount of beneficial nutrients in a food product in proportion to e.g. energy content, weight or amount of detrimental nutrients. Terms such as nutrient rich and micronutrient dense refer to similar properties. Several different national and international standards have been developed and are in use