Is there much uniform agreement on it? Is the classification objectively precise & reliable?

The Harvard School of Public Health acknowledges problems with definition & attempted standards

the definition of processed food varies widely depending on the source

The NOVA system is recognized by the World Health Organization, Food and Agriculture Organization, and the Pan American Health Organization, but not currently in the U.S. by the Food and Drug Administration or USDA. NOVA has been criticized for being too general in classifying certain foods, causing confusion.

Ultra-Processed Foods: Definitions and Policy Issues pointed out that difficulty & inconsistent examples the definers offered to clarify.

Because of the difficulty of interpretation of the primary definition, the NOVA group and others have set out lists of examples of foods that fall under the category of ultra-processed foods. The present manuscript demonstrates that since the inception of the NOVA classification of foods, these examples of foods to which this category applies have varied considerably. Thus, there is little consistency either in the definition of ultra-processed foods or in examples of foods within this category.

Other scholarly review articles criticize the classification as unclear even among researchers.

Processed food classification: Conceptualisation and challenges regarding classifications:

There is no consensus on what determines the level of food processing.

Classification systems that categorise foods according to their “level of processing” have been used to predict diet quality and health outcomes and inform dietary guidelines and product development. However, the classification criteria used are ambiguous, inconsistent and often give less weight to existing scientific evidence on nutrition and food processing effects; critical analysis of these criteria creates conflict amongst researchers.

The classification systems embody socio-cultural elements and subjective terms, including home cooking and naturalness. Hence, “processing” is a chaotic conception, not only concerned with technical processes.

The concept of “whole food” and the role of the food matrix in relation to healthy diets needs further clarification; the risk assessment/management of food additives also needs debate.

Ultra-Processed Foods: Definitions and Policy Issues regarding a single classification system (NOVA):

The present paper explores the definition of ultra-processed foods since its inception and clearly shows that the definition of such foods has varied considerably.

Thus, there is little consistency either in the definition of ultra-processed foods or in examples of foods within this category.

The public health nutrition advice of NOVA is that ultra-processed foods should be avoided to achieve improvements in nutrient intakes with an emphasis on fat, sugar, and salt. The present manuscript demonstrates that the published data for the United States, United Kingdom, France, Brazil, and Canada all show that across quintiles of intake of ultra-processed foods, nutritionally meaningful changes are seen for sugars and fiber but not for total fat, saturated fat, and sodium. Moreover, 2 national surveys in the United Kingdom and France fail to show any link between body mass index and consumption of ultra-processed foods.

Some research articles find the leading definition unreliable: low consistency between nutrition specialists following the same definition.

Although assignments were more consistent for some foods than others, overall consistency among evaluators was low, even when ingredient information was available. These results suggest current NOVA criteria do not allow for robust and functional food assignments.

If experts aren’t able to classify “ultraprocessed” items consistently, then what chance has anyone? At the moment, “processed food” seems more buzz & connotation than substance.

It might make more sense to classify food by something clearer like nutritional content.