A recent British Journal of Nutrition study investigated whether processed foods follow all dietary recommendations.
Study: Nutrients or processing? An analysis of food and drink items from the UK National Diet and Nutrition Survey based on nutrient content, the NOVA classification and front of package traffic light labelling. Image Credit: Niloo/Shutterstock.com
Background
The UK dietary guidelines recommend limited consumption of foods high in saturated fat, added sugar, and salt (HFSS). A higher intake of HFSS elevates the risk of non-communicable diseases, such as obesity, cardiovascular diseases, type 2 diabetes, and mortality.
Typically, the public receives all relevant information on nutrition through multiple strategies, including the front-of-package labeling (FOPL) and the Eatwell Guide.
This information helps consumers make informed decisions about purchasing a food type at the point of purchase.
It must be noted that FOPL systems differ across countries. For instance, in some countries, food labels contain non-interpretive nutrient information, while others follow color-coded nutrient information.
In the UK, a multiple traffic light (MTL) system is followed, i.e., a color-coded system. In European countries, nutritional information is provided by supplying a Nutri-Score.
According to the color-coded FOPL system, green represents a low amber medium, and red represents a high content of nutrients, i.e., fat, saturated fat, salt, sugar, and so on. Previous studies have shown that the food processing system also impacts health in addition to the nutrient content.
Many systems classify food and drink items. For instance, the NOVA classification focuses on categorizing foods and drinks into four groups, namely, minimally processed food (MPF), processed culinary ingredients (PCI), processed food (PF), and ultra-processed food (UPF).
UPFs are industrially formulated products that have poor nutritional profiles. These contain ingredients that make the food highly palatable, cheap, and long-lasting.
The increased consumption of UPF has many adverse effects on health, which subsequently lead to an increase in the risks of non-communicable diseases and all-cause mortality.
It is imperative to understand whether food processing must be considered as a criterion to guide consumers' purchases.
About the study
The current study investigated whether the extent and purpose of the processing of food and drinks influences the nutrient content.
The NOVA classification of UK food and drinks, considered in the National Diet and Nutrition Survey (NDNS) Rolling Programme Year 12 database, was evaluated in accordance with the overlap with FOPL nutritional characteristics and MTL scoring.
The food and drink items considered in the NDNS were coded as MPF, PF, PCI, and UPF following the NOVA classification and FOPL traffic lights system.
A final sample of 2,980 food items were included in the analysis, and over half of them were UPFs. About a third of the food items were classified as MPFs, 2% were PCI, and 9.5% were PFs.
Study findings
Compared to MPFs, UPFs were found to have an unhealthier nutritional profile, but this was not true for PFs.
UPFs contained higher amounts of total sugar, saturated fat, fat, and salt than MPFs. UPFs were more likely to be categorized as hyper-palatable and were more energy-dense.
UPFs and PFs contained similar quantities of salt, saturated fat, and fat, but UPFs had higher amounts of sugar. Furthermore, UPFs had fewer green FOPL traffic lights.
It was noted that not all UPFs had unhealthy nutrient profiles. More than 50% of UPFs did not have a red FOPL traffic light, and a substantial number had FOPL MTL scores similar to MPFs.
However, compared to MPFs, UPFs showed poor nutritional profiles despite no red FOPL traffic light. UPFs were also seen to be more energy-dense compared to PFs and MPFs. These findings indicate that the FOPL MTL system only partially captures the purpose and extent of food processing.
Conclusions
This study showed that UPFs tend to have an unhealthier nutritional profile and a higher energy density than MPFs.
They also had fewer green and more red FOPL traffic lights. In comparison to PFs, UPFs were seen to be more energy-dense. UPFs were also seen to be of poor nutritional quality even if they fared well in the traffic lights system.
The findings suggest a case for rethinking how processing could be used with the UK dietary recommendations, given that some UPFs appear healthy according to the FOPL MTL scores.
The key strength of this study centers around the large nationally representative database on food and drink items coupled with matching information on nutrient compositions.
The main limitation of the study revolves around the criticisms over the use and operationalizability of the NOVA classification.
Healthy low-carb diet and time-restricted eating improve weight loss and gut health beyond calorie restriction