The Evening Standard claim that Health Secretary Alan Johnson has been told to make two million more people adopt active lifestyles by 2012.
The target - a key pledge of the Olympics bid - has shifted departments after a row over who should take responsibility.
The Standard now claims it will form part of the Department of Health's plan to cut obesity rates.
Johnson is expected to take over the quango Active England to deliver the target of convincing people to live healthily.
He will use it to promote healthy lifestyles through a series of Olympic-themed roadshows and mass participation events such as city runs.
As part of the obesity strategy 10 new "fit towns" will also be created, with a £30 million grant to build cycle paths, playgrounds and encourage children to cut out snacks, the Standard report.
Primary school children will be regularly weighed and measured and parents told to check the results using an online "fat calculator".
Pregnant women could also be monitored for body mass index during their 12-week scan to identify babies at risk of obesity.
The full article can be read at http://www.thisislondon.co.uk/standard/article-23433059-details/Olympics at centre of new anti-obesity drive/article.do.
Michael Bradley Photography