Professor Theresa Marteau and her team conducted a Cochrane systematic review producing conclusive evidence that people consume more food and drink when offered larger-sized portions, packages or tableware.

The Behaviour and Health Research Unit (BHRU) is based in Cambridge’s Department of Public Health and Primary Care. Funded by the UK Department of Health Policy Research Programme, it contributes evidence to national and international efforts to achieve sustained behaviour change to improve health outcomes and reduce health inequalities. The unit focuses on the excessive consumption of food and alcohol, inactivity and smoking, as changing these behaviours positively would help to prevent the majority of the preventable non-communicable diseases, including many cancers, cardiovascular disease and diabetes.


After conducting scoping exercises, the unit realised that there was a large body of evidence around portion, package and tableware sizes which was of significant policy relevance, yet which hadn’t been brought together. During the course of over two years, the team carried out a complex Cochrane review, which was published in September 2015. The research was followed up with a BMJ piece entitled Downsizing: What are the policy options for reducing portion sizes to help tackle obesity? 


The review evidence showed that people consume more food and non-alcoholic drink when offered larger portions, packaging or tableware rather than smaller sizes, regardless of other factors such as gender, BMI or self-control. Although perhaps an intuitive finding, until this review, we did not have the best evidence to show this. The review’s findings suggest that cutting the size of portions, packages and tableware may present a potential path for helping to tackle obesity, which impacts a quarter of British adults, costing lives, quality of life and the NHS. 

To read the case study in full, visit the Cambridge Institute for Public Health website at