In the 1960s people were slimmer simply because they were more active, according to the British government.
Since then obesity rates in English adults have risen from 1-2 percent to around 26 percent, figures show.
Still, overweight adults of today are far less likely to try to lose weight, a repeat of a survey done in 1967 showed.
Plus adults in the 1960s did more housework and used the car less, the Department of Health said.
The Department of Health carried out the survey to promote the Change4Life campaign, reports The BBC.
Professor Alan Maryon-Davis, president of the faculty of public health, said people are probably healthier these days in terms of life expectancy.
"But we have these problems which are problems of affluence and we need to get back to being more physically active.
"One observation I would make is that overweight people in the 1960s were less common so they may have been more inclined to get back to a normal weight - it's about social norms."
A Department of Health spokesperson said: "In the 60s our daily routines involved more exercise which helped people stay slimmer.
"Nowadays, our increasingly sedentary lives paired with the proliferation of a wide range of unhealthy foods have combined to create a very difficult environment for people to reach and maintain a healthy weight."