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.