Exposure to processing from ultraprocessed diets and in feeding studies

Area of Science:

• Nutrition Science
• Food Science
• Public Health

Background:

• Current food processing classifications are categorical, hindering interpretation of dietary exposures and health impacts.
• Existing studies on ultra-processed foods show heterogeneity, making it difficult to isolate processing effects.
• A quantitative approach is needed to accurately assess cumulative exposure to food processing.

Purpose of the Study:

• To introduce a transformation-based framework (Food Processing Levels, FPL) to quantify food processing.
• To develop Processed Food Intake (PFI)-based descriptors for cumulative processing exposure.
• To enable comparison of diets differing in processing history, even when matched for nutritional quality.

Main Methods:

• Distinguishing physical and chemical food modifications using the Food Processing Levels (FPL) framework.
• Deriving Processed Food Intake (PFI) descriptors to quantify cumulative processing exposure.
• Analyzing heterogeneity in ultra-processed food (UPF) classifications and comparing processing exposure quantitatively.

Main Results:

• Categorical classifications of diets (e.g., UPF) show wide variation and overlap in cumulative processing exposure.
• Quantitative PFI descriptors reveal graded differences in processing exposure obscured by categorical methods.
• Item-weighted, energy-weighted, and nutrients-weighted PFI descriptors enable nuanced dietary comparisons.

Conclusions:

• Treating food processing as a continuous dietary exposure provides a reproducible analytical basis.
• This quantitative approach enhances the interpretation of intervention designs and experimental outcomes.
• It facilitates studies specifically testing the health relevance of varying levels of food processing.