Nutrient Density.

The term "nutrient density" refers to the proportion of micronutrients found within a particular food in comparison to that food’s overall calories. Sometimes described as being nutrient rich or micronutrient dense, nutrient-dense foods are typically considered to be the healthier counterpart of energy-rich or nutrient-poor foods, which are those containing a significant amount of calories but a correspondingly low proportion of nutrients. Foods typically considered nutrient dense include leafy greens such as spinach, fish such as salmon, and whole-grain products such as whole-wheat flour or cereal. Nutrient density is particularly important in light of the serious ramifications of nutrient deficiency. Among the essential nutrients found in many nutrient-dense foods are iron, iodine, and vitamin A, deficiencies of which can cause major health problems. In light of such risks, some food manufacturers add essential micronutrients to certain foods, thus improving their nutrient density through a process known as "fortification."