Almost three-quarters of Britons in a survey believe they are overweight and have vowed to start a health campaign in the New Year.
But it appears only the young are concerned about controlling their weight, with just a quarter of older Britons seeing getting fit as a priority, the poll for the Community Service Volunteers (CSV) charity found.
Despite almost 70 percent of Britons saying they want to get healthy, experts said other evidence into people's behaviour suggests that repeated warnings about the dangers of obesity is falling on deaf ears.
The survey, commissioned by CSV subsidiary Dare to Care and based on an ICM poll of 1,032 adults, showed that those in the northeast and Scotland are most concerned about their weight.
While more than two thirds of people aged between 18-44 are most concerned about staying fit, just one in four of those in the baby boomer ages of 55 to 64 thought losing weight was a priority, the study found.
A third of all ages said they would make a New Year resolution to lose weight and get fit, it found.
But the poll came a day after the fast-food giant, McDonalds revealed it had recorded growth rates close to their peak of the 1980s -- with 88 million visits to its outlets in the UK last month alone.
Obesity causes 9,000 premature deaths each year in England and costs the NHS about one billion pounds annually.
A recent government study predicted that half the population could be obese within 25 years.
Colin Waine, chairman of the National Obesity Forum charity, said the country's obesity crisis was "quite dire".
While it appears people want to tackle obesity, evidence such as the sales figures revealed by McDonalds, paints a markedly different picture.
"It would suggest that the concerns are not being matched by behaviour," the former GP told Reuters.
He said that if current trends continue, by 2020 a fifth of the National Health Service budget will be consumed by treating type 2 diabetes, which, with heart disease and certain cancers, is directly linked to obesity.
In October, the government unveiled a strategy where parents of severely overweight children may be sent letters warning them of the health dangers involved.
Health Secretary Alan Johnson has said obesity could lead to a "potential crisis on the scale of climate change".
