Nutrient Heatmap
Visual comparison of 100 popular foods across 30 key nutrients. Darker cells indicate higher nutrient density per 100 g.
How to Read This Heatmap
Each row is a food and each column is a nutrient. Cell colour shows how that food ranks for that nutrient compared to all other foods shown: darker blue = higher content. Values are shown per 100 g by default (switch to "per 100 kcal" for nutrient density). Click any column header to sort foods by that nutrient. Click the food name to view its full profile.
Tip: Use the food group filter to compare within a category (e.g., all vegetables, or all fish). The "per 100 kcal" mode is especially useful for finding nutrient-dense foods regardless of calorie content.
Why Use a Nutrient Heatmap?
Nutrient data is traditionally presented in tables or on labels — one food at a time. This makes it difficult to answer questions like "which vegetables have the most iron?" or "how does salmon compare to other protein sources across all micronutrients?" A heatmap solves this by displaying many foods and many nutrients simultaneously, using colour intensity to encode values.
With the heatmap, you can quickly identify:
- Nutrient-dense all-rounders — foods with consistently dark cells across many columns, indicating they are rich in multiple nutrients (liver, kale, and sardines typically stand out).
- Single-nutrient champions — foods with one very dark cell but light cells elsewhere, indicating they are an exceptional source of one specific nutrient (e.g., Brazil nuts for selenium).
- Nutritional gaps — foods with mostly light cells, indicating low nutrient density relative to other foods shown.
- Within-group differences — filtering by food group reveals which specific items within a category (e.g., fish, grains, or fruits) offer the best nutritional value.
The heatmap is a visual complement to the food search (for finding specific foods) and the comparison tool (for detailed side-by-side analysis of 2-5 foods).
Per 100 g vs. Per 100 kcal: Which Should You Use?
The toggle between "per 100 g" and "per 100 kcal" changes the fundamental basis of comparison and can dramatically change the rankings:
- Per 100 g (by weight) — Shows how much of each nutrient you get in a fixed weight of food. This is useful when you think about food in terms of portions and preparation. Dense, calorie-rich foods like nuts and cheese can appear very nutrient-rich by weight because you are evaluating a large amount of calories.
- Per 100 kcal (by energy) — Shows how much of each nutrient you get per calorie. This reveals true nutrient density — foods that pack the most vitamins and minerals per unit of energy. Leafy greens, which are very low in calories, jump to the top in this mode because their nutrients come at almost zero calorie cost.
For most practical purposes, the per-100-kcal view gives the more actionable picture: it tells you which foods deliver the most nutrition relative to their calorie contribution to your diet. This is the same basis used by the NRF9.3 nutrient density score on individual food pages.
Frequently Asked Questions
What nutrients are included in the heatmap?
The heatmap includes 30 key nutrients across four categories: macronutrients (protein, fat, carbohydrates, fibre), 11 minerals (calcium, iron, magnesium, phosphorus, potassium, sodium, zinc, copper, manganese, selenium, fluoride), core vitamins (A, C, D, E, K1, B1, B2, B3, B5, B6, B12, folate, choline), and omega-3 fatty acids. These represent the nutrients most commonly searched for and most relevant to dietary adequacy.
Why do some cells show "—"?
A dash (—) means the nutrient value is not available in our database for that food. Not all foods have been analysed for all nutrients. This is normal — even the most comprehensive food composition databases have gaps. The data completeness varies by food and nutrient.
How are the colours calculated?
For each nutrient column, values are ranked from lowest to highest across all visible foods. The colour intensity represents the percentile rank: lightest = lowest values, darkest blue = highest values. This is a relative comparison — the same food may appear darker or lighter depending on which other foods are shown.
What is the difference between "per 100g" and "per 100 kcal"?
"Per 100 g" shows absolute nutrient content by weight, which is useful for comparing equal portions. "Per 100 kcal" normalises by energy content, revealing nutrient density — how many nutrients you get per calorie. Foods like leafy greens rank much higher per calorie than per weight because they are very low in calories.