Efforts in recent years to get restaurants, movie theaters, sports arenas and other venues to stop super-sizing their food and drink offerings haven’t been all that successful.
Those efforts have also been steeped with controversy. Would such efforts actually help stem and reverse the growing obesity epidemic in the U.S. (and elsewhere)? Would people eat or drink less if serving sizes were smaller? And, more important, would those smaller sizes help them maintain a healthier weight?
Results from a new study — one its authors say offers “the most conclusive evidence to date” on the topic — suggests that the answers to those questions is “yes.”
“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 Gareth Hollands, one of the study’s authors and a senior researcher at the British government-funded Behaviour and Health Research Unit, in a released statement.
The study, published Monday in the Cochrane Database of Systematic Reviews, is a meta-analysis of 61 previously published studies that examined how portion size influences people’s food and drink consumption. All the studies were considered “high quality” (randomized and controlled), and together involved more than 6,700 participants.
After reviewing the data from these studies, Hollands and his colleagues determined that eliminating larger-sized servings completely from the diet could reduce the amount of calories consumed among U.S. adults by 22 to 29 percent.
That’s as many as 527 calories a day.
For British consumers, the numbers were slightly lower: a reduction of up to 12 to 16 percent of total energy consumed, or 279 calories a day.
Overall, the meta-analysis suggests, write its authors, “that acting to reduce the size, availability and appeal of larger-sized portions, packages and tableware has potential to reduce the quantities of food that people select and consume by meaningful amounts.”
Limitations and caveats
The study’s findings come, of course, with some caveats.
“It is uncertain whether reducing portions at the smaller end of the size range can be as effective in reducing food consumption as reductions at the larger end of the range,” the reviewers note.
It’s also unclear, they add, whether changing portion sizes would translate into any sustained or meaningful reduction in the consumption of calories over the long term.
People denied super-sized foods and drinks might consume those calories in other ways — by eating more often, for example.
Still, “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,” said Hollands.