A new study has confirmed what has long been suspected - if you are served bigger portions of food, you will consistently consume more.

Overeating is known to increase the risk of a number of diseases including heart disease, diabetes and some cancers. However until now, it has been unclear what impact the ‘overserving' of larger portions has on the consumption of food and drink.

UK researchers decided to look into this further. They assessed 61 studies on this topic, involving over 6,700 participants. The studies looked at the influence of portion size, package size and tableware size on the consumption of food.

The results show that people consistently eat and drink more if they are offered larger size portions, packages or tableware compared to when they are offered smaller-sized versions.

"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," explained lead researcher, Dr Gareth Hollands, of the University of Cambridge.

He noted that the situation is actually ‘far more complex', and environmental influences clearly have a big role to play.

"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," he suggested.

The results were similar in men and women irrespective of their body mass index (BMI).

However, the researchers acknowledged that currently, ‘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," they commented.

Details of these findings are published in the Cochrane Database of Systematic Reviews 2015.