Are your ready meals getting smaller or larger?

Last week Public Health England announced an enquiry into portion sizes in pizza ready meals and snacks eaten by children as part of an initiative to cut obesity. But have portion sizes changed over the years and do they matter?

Here are some examples of research.
Public Health England has published some facts about the scale of the problem
It includes discussion of some of the possible causes. They include this Foresight report which considers the impact of environment and calories laiden food as significant.
For further sources on discussion of the link between portion size and weight see the Harvard University website. This has an obesity prevention source which has news and links to recent reports and other research  It also has a good section on the toxic food environment
The Cochrane database of systematic reviews also has some examples of detailed literature reveiws relatign to the evidence on obesity and obesity treatments.
Pubmed from the National Library of Medicine also has some useful full text and abstract from articles based on scientific evidence. It includes an article on portion size which reviews the evidence that people eat more when given larger portion sizes and in general portion sizes have increased over the last few decades.
NHS evidence has references and some full text articles, guidelines and documents from the NHS and other major scientific journals
Other useful sources for news and comment are the National Obesity Forum which has commented on the UK government's methods of reducing calories and British Heart Foundation whose portion distortion report 2013 found evidence of increasing sizes and calories in ready meals.
Indeed the UK government has  reacted to these concerns and recent guidelines for sugar control have been introduced.
However from a different perspective  the Office for National Statistics has recently considered “shrinkflation” – where manufacturers reduce the package size of chocolate  whilekeeping the cost to the consumer the same.