People tend to fill their plate when they sit down for a meal - and do not stop eating until their plate is clean.
By using smaller tableware, they will put less food on their plate in the first place.
Ian Shemilt, who co-led the study published by the influential Cochrane Library, said that people use plate size as an 'anchor' to determine the appropriate amount to eat.
"This in turn results in us unknowingly selecting and eating more food," the Cambridge University academic said.
"You tend to serve less food on plates that are smaller."
Dr Gareth Hollands, from the university's Behaviour and Health Research Unit, who co-led the analysis of 61 separate studies involving 6,711 participants, said: "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.
"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."
In their conclusions, the researchers wrote that people "consistently consume" more food and drink when offered larger-sized portions, packages or tableware.
They added: "This suggests that policies and practices that successfully reduce the size, availability and appeal of larger-sized portions, packages, individual units and tableware can contribute to meaningful reductions in the quantities of food people select and consume in the immediate and short term."
The researchers also called for retailers to stop discounting food sold in larger quantities.
Mr Shemilt added: "At the moment, it is all too easy - and often better value for money - for us to eat or drink too much.
"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."
Professor Brian Ratcliffe, an expert in nutrition at Robert Gordon University in Aberdeen, said: "Presumably related to a lack of effective self-restraint, people seem to be reluctant to leave or waste food and so consume what they are served or find larger portions more attractive."
Dr Alison Tedstone, chief nutritionist at Public Health England, said: "This study clearly demonstrates that reducing portion sizes is a successful way to cut calories.
"Given that almost two-thirds of adults are overweight or obese, it's important to keep an eye on portion sizes when cooking, shopping and eating out to avoid over-eating and help maintain a healthy weight."
