Simply put, energy density is the number of calories (energy) in a specific amount of food. High energy density means that there are a lot of calories in a small amount of food. Low energy density means there are few calories in a large amount of food.
https://www.msn.com/en-us/health/nutrition/weight-loss-feel-full-on-fewer-calories/ar-AA1cnieC?ocid=msedgntp&cvid=235b111d2e964e279f284468bae41509&ei=17
Mws R Writings 