Most commonly, nutrient density is defined as a ratio of nutrient content to the total energy content. Nutrient-dense food is opposite to energy-dense food (also called "empty calorie" food). [...] Fruits and vegetables are the nutrient-dense foods, while products containing added sugars, processed cereals, and alcohol are not.
This is why replacing added sugar with anything that contains at least some vitamins and/or minerals is beneficial.
http://en.wikipedia.org/wiki/Nutrient_density
Most commonly, nutrient density is defined as a ratio of nutrient content to the total energy content. Nutrient-dense food is opposite to energy-dense food (also called "empty calorie" food). [...] Fruits and vegetables are the nutrient-dense foods, while products containing added sugars, processed cereals, and alcohol are not.
This is why replacing added sugar with anything that contains at least some vitamins and/or minerals is beneficial.