Simply reducing portion sizes is not an easy solution to reducing energy intakes as results from laboratory based experiments do not necessarily reflect what happens in the real world, according to a new review.
The scientific review, published in Critical Reviews in Food Science and Nutrition, ​analysed the scientific evidence available on portion sizes, asking what exactly is already known about the influence of portion size on energy intake, and what additional information still needs to be established.
Written by Professor David Benton from Swansea University, the review notes that there is increasing evidence that the portion sizes of many foods have increased "and in a laboratory at least this increases the amount eaten​." However, he said that such conclusions are limited by the complexity of the issue.
Benton suggested that while it may be established in laboratory settings that larger portion sizes lead to increased food intake; the way that portion size interacts with the 'multitude' of factors that determine food intake in a real world setting has not been established.
"The single most important objective is to establish the importance of portion size relative to the range of other variables that influence food intake,"​ said the expert, who reiterated that laboratory findings linking increased portion size to higher food intake cannot be taken in to the real word.
Benton added that the findings from the review highlight the complexities surrounding the UK Government's Public Health Responsibility Deal's call for reduced portion sizes as a way of obtaining reductions in caloric intakes.
He warned that concerns about portion size need to be part of a multi-faceted approach to the topic, suggesting that it is 'unlikely' that any single change is going to have a significant impact.
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