Nutrient density
The ratio between the amount of beneficial nutrients (vitamins, minerals, fibre) in a food and its calorie content, helping identify the most nutritionally "rewarding" foods.
A food with high nutrient density provides a lot of micronutrients for few calories. Examples: green vegetables, liver, eggs, oily fish, berries. Conversely, “empty calories” (fizzy drinks, sweets, alcohol) provide energy without nutrients.
An original angle (not to be confused with energy density): nutrient density is often mixed up with energy density (calories per gram). They are two different things that are useful together:
- Low energy density + high nutrient density = ideal for satiety and health (vegetables, fruit)
- High energy density + low nutrient density = a trap (crisps, sweets)
A food can be calorific AND nutritious (nuts, avocado, olive oil): these are valuable but need portioning. Another can be low in calories AND in nutrients (iceberg lettuce): not much use nutritionally.
In practice: the concept of “nutrient density” has inspired scores such as the ANDI (Aggregate Nutrient Density Index), which ranks foods. Kale, cabbage and spinach dominate the top of the ranking.
But a caveat: optimising nutrient density alone can lead to unbalanced diets (an obsession with “superfoods”). “Less dense” foods (cereals, starchy foods) have their place for energy and the microbiota. Overall balance matters more than the score of each food.