The London borough of Newham, which hosted the 2012 Olympics, is the least physically active place in England, a report reveals.
The organisation, UKActive, found about four in every 10 adults in Newham fail to do even 30 minutes of moderate-intensity exercise a week.
This is despite a government pledge to use the Games to create a lasting legacy of fitness.
Public Health England said councils were working hard to get people moving.
Best and worst
Overall, 29% of people in England are classed as physically inactive (doing less than 30 minutes of moderate exercise, such as cycling or fast walking, a week).
Newham had the lowest levels of activity in the country, with 39% of residents inactive.
Including Newham, 13 out of the 15 least active local authorities are deprived areas.
Regions with the best track records of activity tended to be more affluent - Richmond upon Thames came out top with 84% of its residents doing the minimum amount of exercise or more.
UKActive looked at 150 local authorities in England for the study. It says the results are not about good and bad in terms of performance in tackling inactivity - Newham has pledged one of the country's biggest investments, £2.1m in 2014-15.
Data shows that more than 70% of councils have raised their allocated budget on physical activity. Councils allocated 4% of their public health grant to tackling inactivity in 2014-15 compared with 2% in 2013-14.
David Stalker, the not-for-profit organisation's CEO, said: "We've known for some time that we're facing an uphill battle to reverse the inactivity trend and while the increase in funding represents a seismic shift in thinking amongst local authorities, building a sound evidence base to underpin the activity will be the ultimate difference between success and failure."
Prime Minister David Cameron said the government had made it clear that departments would work together to "embed physical activity into the DNA of the nation" as part of the long-term physical activity legacy from the 2012 Games.
Ann Hoskins, director of the Healthy People division at Public Health England said: "Getting everybody active every day can be achieved in a variety of ways and councils are a key pivot point in terms of moving the agenda forward.
"Healthy environments support health and recreation and wellbeing. The council is key to this but cannot shift the population in isolation. Getting everybody active every day requires a change across the whole system, from workplaces to care homes, everyone has a role to play."
Experts recommend adults do 150 minutes of moderate activity over the course of a week for good health.