Researchers from the University Medical Center Groningen developed the Ultra-processed food (UPF) categorization for adults according to the NOVA classification using the Food Frequency Questionnaire Sum scores from the heart of the FFQ flower (1A Questionnaire 2). (sections: Nutrition and secondary & linked variables).

The UPF food categorization can be requested in the Lifelines catalogue or by mail (data@lifelines.nl). When this data has been used in your research, you will have to include a reference to the the following paper:

• Duan, M. J., Vinke, P. C., Navis, G., Corpeleijn, E., & Dekker, L. H. (2022). Ultra-processed food and incident type 2 diabetes: studying the underlying consumption patterns to unravel the health effects of this heterogeneous food category in the prospective Lifelines cohort. BMC medicine, 20(1), 1-11.

From the paper of Duan et al. (2022)
Research on UPF has been facilitated by the development of the NOVA classification. The NOVA classification is a frequently used method to categorize food and drinks based on the nature, extent, and purpose of food processing. The NOVA classification comprises four categories, ranging from un-processed/minimally processed food to UPF. According to the NOVA classification, UPF is mostly formulated from food substances and industrial ingredients that undergo a series of chemical and physical manufacturing processes. The resulting food products are often pre-packed, contain little or no intact (un-processed) food, and are considered microbiologically safe, convenient, and palatable.

Using the NOVA classification, the 110 food items from the FFQ heart were categorized in four proposed categories:

1. Unprocessed or minimally processed food: for example fresh vegetables or fruits and unprocessed meat
2. Processed culinary ingredient: for example butter or oil for cooking, sugar, and salt
3. Processed food: for example canned vegetables or fish and fruits in syrup
4. Ultra-processed food: for example processed meat, soft drinks

Per category three types of variables have been created:

• Classification variable: which adds up the intake of all food items that belong to the specific category
• Intake (nova) weight ratio variable: which indicates the weight proportion (% grams) of a specific category in the total diet of a day
• Intake (nova) energy ratio variable: which which indicates the energy ratio (grams/1000kcal) of a specific category in the total diet of a day

1. The current categorization doesn't specifically handle the Betrouwbaarheid of energy intake (provided in the Food Frequency Questionnaire Sum scores). This could be a decision for other researchers using the UPF classification data.
2. According to the NOVA classification, some alcohol products should also be characterized as ultra-processed food. However, we did not do this because alcohol may have separate health effects. Therefore, we analyze alcohol intake always as a separate covariate. This is also practiced by other papers from other cohorts.