Rationale and methodological justification AminoFit
AminoFit was developed by Maaike van Bree and Hinke Kruizenga, dietitian-researchers at Amsterdam UMC, and blockchain developer Bouke Stam, as part of the PEARLS project.
The nutritional data used by the AminoFit tool are derived from publicly accessible datasets. A comprehensive collection of products has been compiled to the greatest extent possible. This page outlines which datasets were used and the decisions made in the process. All steps are documented in a logbook, which can be requested via info@voedingenbeweging.nu.
The datasets listed below were utilized, combined with the portion size data of food products from RIVM.
Frida Fooddata
Frida is the public food database of the Danish National Food Institute at the Technical University of Denmark. The May 2024 version of the Frida database was used (revision 5.2, published on May 31, 2024).
FoodData Central
FoodData Central is an integrated, research-focused data system from the U.S. Department of Agriculture (USDA) that provides comprehensive information on nutrients, including amino acids.
MEXT
The Japanse MEXT database, managed by the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT), provides nutritional values for a wide range of foods, including amino acid composition. The database is regularly updated.
Composite Dishes
The dataset also includes composite dishes, such as chili sin carne or lasagna. The recipes for these dishes have been developed and calculated per 100 grams using AminoFit. The ingredients used for each dish can be found in this file.
Daily Essential Amino Acid Requirements
For calculating the amino acid profile, the guidelines of the World Health Organization (WHO) have been followed. A meal’s amino acid profile is considered adequate if the combined products supply amino acids in the proportions listed below.
The unit for these reference values is mg per gram of protein. A meal may have a good amino acid profile but contain insufficient protein overall. It is essential to evaluate meals based on both the protein quantity and the amino acid profile.
| Essential amino acid | Requirement (mg / gram protein) |
| Histidine | 15 |
| Isoleucine | 30 |
| Leucine | 59 |
| Lysine | 45 |
| Methionine + Cysteine | 22 |
| Phenylalanine en Tyrosine | 38 |
| Threonine | 23 |
| Tryptophan | 6 |
| Valine | 39 |
Digestibility factors
In March 2023, Samantha Heerschop from WUR published the analysis: Shifting towards optimized healthy and sustainable Dutch diets: impact on protein quality in the European Journal of Nutrition.
To include digestibility in the analysis, she categorized it within the NEVO product groups. The table provides a summary of this classification. The complete table and explanation can be found here. These digestibility factors have been integrated into AminoFit.
| Productgroup | Digestibility factor |
| Potatoes and tubers | 0,55 |
| Bread | 0,9 |
| Eggs | 0,97 |
| Fruit | 0,76 |
| Pastries and cookies | 0,9 |
| Vegetables | 0,65 |
| Cheese | 0,95 |
| Mixed dishes, snacks, or sandwich fillings with animal products | 0,9 |
| Mixed dishes, snacks, or sandwich fillings on a plant basis | 0,65 |
| Grains | 0,7 |
| Milk and dairy products | 0,95 |
| Nuts and seeds | 0,75 |
| Legumes | 0,75 |
| Fish | 0,9 |
| Meat and poultry | 0,95 |
Meat substitutes and dairy substitutes | 0,94 |
Protein and energy requirements per meal
To establish a standard for the amount of energy and protein per meal occasion in a healthcare institution, the energy and protein requirements were calculated for 2,568 patients at Amsterdam UMC (both locations), OLVG (both locations), and BovenIJ Hospital. These patients participated in the ProIntens study.
The results are shown in the table on the right. Based on this, the generic standard for protein is set at a minimum of 70 grams and an optimum of 85 grams per day, and for energy, a minimum of 1,750 kcal and an optimum of 2,000 kcal per day.
Per meal, this amounts to:
| Meal | Energy (kcal) | Protein (gram) |
| Breakfast | 400 – 500 | 20 – 25 |
| in-between morning | 150 – 200 | 5 – 10 |
| Lunch | 400 – 500 | 20 – 25 |
| In-between afternoon | 150 – 200 | 5 – 10 |
| Diner | 500 – 600 | 20 – 25 |
| In-between evening | 150 – 200 | 5 – 10 |
| TOTAL | 1750 – 2200 | 75 – 105 |
| Energy requirements | Proten requirements | |
| Mean (SD) | 1881 (335) | 83 (16) |
| 25e percentile | 1655 | 71 |
| Median | 1890 | 83 |
| 75e percentile | 2120 | 95 |
| Minimum | 680 | 36 |
| Maximum | 2780 | 150 |
The calculations in AminoFit
The data from the Frida and FoodData Central datasets have been combined into an Excel file. Digestibility factors have been added to this file. The AminoFit tool retrieves data from this combined Excel file, while portion sizes come from a separate Excel file provided by RIVM.
The following calculations have been applied:
- mg EAA per g protein (per product) = (mg EAA per 100 g product / 100) / (grams of protein per 100 g product / 100)
- Protein amount per product (adjusted for quantity and digestibility) = (grams of protein per 100 g product / 100 * number of grams) * digestibility factor
- Protein amount in the entire meal = the sum of the above
- mg EAA total per product = mg EAA per gram of protein per product * protein amount per product (adjusted for quantity and digestibility)
- mg EAA per g protein in the meal = sum of mg EAA per product / total amount of protein adjusted for quantity and digestibility
- Amino acid score = (mg EAA per g protein in the meal / EAA reference value according to WHO