The findings, published in the Cochrane Database of Systematic Reviews, suggests that eliminating larger-sized portions from the diet completely could reduce energy intake by up to 16% among UK adults or 29% among US adults.
Co-led by Dr Gareth Hollands at the University of Cambridge, the team behind the new Cochrane review noted that while it is known that overconsumption of food and drinks increases the risks of heart disease, diabetes, and many cancers, which are among the leading causes of ill health and premature death – the extent to which this overconsumption might be attributed to ‘overserving’ of larger-sized portions of food and drink has until now not been known.
Hollands and his colleagues performed a systematic review of the evidence which combined results from 61 high quality studies, and data from 6,711 participants, to investigate the influence of portion, package and tableware size on food consumption.
“It may seem obvious that the larger the portion size, the more people eat, but until this systematic review the evidence for this effect has been fragmented, so the overall picture has, until now, been unclear,” said Hollands. “There has also been a tendency to portray personal characteristics like being overweight or a lack of self-control as the main reason people overeat.”
“In fact, the situation is far more complex. Our findings highlight the important role of environmental influences on food consumption. Helping people to avoid ‘overserving’ themselves or others with larger portions of food or drink by reducing their size, availability and appeal in shops, restaurants and in the home, is likely to be a good way of helping lots of people to reduce their risk of overeating.”
According to the team behind the study, the review data showed that people consistently consume more food and drink when offered larger-sized portions, packages or tableware than when offered smaller-sized versions.
This suggests that if sustained reductions in exposure to large sizes could be achieved across the whole diet, it could reduce average daily energy consumed from food by 12% to 16% among adults in the UK (equivalent of up to 279 kcals per day) or by 22% to 29% among US adults (equivalent of up to 527 kcals per day).
“At the moment, it is all too easy – and often better value for money – for us to eat or drink too much,” commented Ian Shemilt, who also co-led the review. “The evidence is compelling now that actions that reduce the size, availability and appeal of large servings can make a difference to the amounts people eat and drink, and we hope that our findings will provide fresh impetus for discussions on how this can be achieved in a range of public sector and commercial settings.”
The researchers did not find that the size of this effect varied substantively between men and women, or by people’s body mass index, susceptibility to hunger, or tendency to consciously control their eating behaviour.
The team also highlighted a range of potential actions that could be taken to reduce the size, availability or appeal of larger-sized portions, packages and tableware, including: upper-limits on serving sizes of energy-dense foods and drinks (for example, fatty foods, desserts and sugary drinks), or on the sizes of crockery, cutlery and glasses provided for use in their consumption; placing larger portion sizes further away from purchasers to make them less accessible; and demarcating single portion sizes in packaging through wrapping or a visual cue.
Other potential actions include: restricting pricing practices whereby larger portion and package sizes cost less in relative (and sometimes absolute) monetary terms than smaller sizes and thus offer greater value for money to consumers; and restricting price promotions on larger portion and package sizes, said the Hollands and his colleagues.
Source: Cochrane Database of Systematic Reviews
Published online, Open Access, doi: 10.1002/14651858.CD011045.pub2
“Portion, package or tableware size for changing selection and consumption of food, alcohol and tobacco”
Authors: Gareth J Hollands, Ian Shemilt, et al