How We Calculate Nutrient Density
“Nutrient-dense” means a food carries a lot of nutrition for its calories. USDA FoodData Central gives the nutrient content per 100 grams; we turn that into one comparable score.
The score
For each of eight nutrients we take the food's amount as a share of the FDA Daily Value, capped at 1.0 (100%):
| Nutrient | Daily Value |
|---|---|
| Protein | 50 g |
| Fibre | 28 g |
| Calcium | 1,300 mg |
| Iron | 18 mg |
| Magnesium | 420 mg |
| Potassium | 4,700 mg |
| Vitamin C | 90 mg |
| Vitamin A | 900 µg RAE |
score = ( sum of the eight capped shares ) × 100 ÷ calories per 100 g
Multiplying by 100 / calories puts every food on a “per 100 kcal” footing, so a calorie-dense food cannot win just by being concentrated. Spinach scores far above olive oil even though oil has more of some nutrients by weight.
What's included
- Only basic and whole foods (USDA SR Legacy and Foundation) — not branded packaged products, whose nutrient panels are sparse and manufacturer-reported.
- Foods must have calcium, iron and potassium on file, so every score rests on a real nutrient panel.
- Foods under 20 kcal per 100 g are excluded, because dividing by a tiny calorie count produces meaningless spikes.
What it is not
- It is not a health rating or a recommendation. It ignores sodium, added sugar, saturated fat, portion size and how a food is actually eaten.
- Eight nutrients is a deliberate, limited basket. Other density indices (for example the USDA's own) use different nutrient lists and give different rankings.
- Capping each nutrient at 100% of the Daily Value stops a single fortified nutrient from dominating.
Sources: U.S. Department of Agriculture, FoodData Central; U.S. Food and Drug Administration Daily Values (21 CFR 101.9). Back to the most nutrient-dense foods.