The study, published in the European Journal of Clinical Nutrition, investigated how different reference amounts used in front of package nutrition labelling systems influence consumers’ evaluations of product healthfulness.
Led by Professor Monique Raats from the University of Surrey – in conjunction with the European Food Information Council (EUFIC) – the research team questioned more than 13,000 consumers from six European countries - finding that overall, people can correctly rank foods according to their objective healthfulness but that the use of different reference amounts and ‘portion sizes’ can cause some confusion.
“Overall, people correctly ranked foods according to their objective healthfulness as defined by risk nutrients alone, and could distinguish between more and less healthful variants of foods,” wrote the team.
However, they noted that the use of different ‘reference amounts’ such as ‘per 100 grams’ or ‘per portion’ had the potential to cause confusion and lead to inaccurate ratings of nutritional values – especially in cases where a ‘per 100 gram’ value differs greatly from a ‘per portion’ value.
Legislation in the EU requires a mandatory nutrition declaration on pre-packed foods expressed ‘per 100g’ or ‘per 100ml’ on back of pack, but this can also be supplemented by nutrition information ‘per portion’ on the front of pack.
As a result, the selection of appropriate reference amounts is central to current debates within the scientific community and policy makers regarding nutrition profiling systems and their ability to classify foods according to their healthfulness, said the study authors.
Raats and her team recruited a total of 13,117 participants from six European countries (Germany, UK, Spain, France, Poland and Sweden) took part in an online experiment in which they rated foods (biscuits, sandwiches, yogurts) on their healthfulness using nutrition labels derived from differing reference amounts; ‘typical portion’, ‘half typical portion’ and ‘per 100g’.
The study revealed that overall, participants correctly ranked foods according to their objective healthfulness and could distinguish between more and less healthful variants of foods with the nutrition labels provided.
However, Raats and her colleagues also found that where the reference amount was very different from the ‘typical’ portion size - as was the case for foods such as biscuits - foods with a ‘per 100g’ label were rated significantly less healthful than when the nutrition labels were presented as ‘typical’ or ‘half typical’ portions.
Comparing country ratings, the team noted that French consumers displayed a tendency to rate most extreme for both the less healthful and the more healthful variants of the foods, whereas in Poland, participants did not differentiate as much between more and less healthful variants.
“Consumers do factor the reference amount, that is, the quantity of food for which the nutritional information is being presented, into their judgements of healthfulness,” concluded the team. “Therefore, appropriate reference amounts are also of importance for the effective presentation of nutritional information.”
Source: European Journal of Clinical Nutrition
Published online ahead of print, doi: 10.1038/ejcn.2014.190
“Reference amounts utilised in front of package nutrition labelling; impact on product healthfulness evaluations”
Authors: M M Raats, S Hieke, C Jola, C Hodgkins, J Kennedy, J Wills