Nutrient density is the concept of eating food that are very nutritious relative to the number of calories. A high nutrient-dense cood provides at least 5% of the recommended daily allowances of one or more nutrients for the lowest caloric cost.
Empty calories in food is a low in nutrients. They don't provide more than 5% of the recommended daily allowance for any nutrients. These foods are high in fat, sugar or alcohol. Try to avoid eating food with empty calories.