Nearly two-thirds of adults in Cornwall were estimated to be overweight or obese last year, new figures show.
Obesity Health Alliance said the government must make it easier and cheaper to buy healthier food and drinks to bring the rate of obesity down in England.
Figures from the Office for Health Improvement and Disparities show an estimated 65.5% of over 18 year olds in Cornwall were overweight or living with obesity in the year to November 2022.
It is up from 60.3% in 2015-16 when the Sport England Active Lives survey began, which the data is based on.
In addition, an estimated 26.7% adults were obese – an increase from 22.8% seven years prior.
Katharine Jenner, Obesity Health Alliance director, said: "These new figures cover a period during which the Government had a ‘oven ready’ obesity strategy that could have helped prevent the continued rise in obesity rates, yet failed to enact it, and now we are reaping the consequences.
"Our country is flooded with cheap, unhealthy, heavily processed food and billions is spent on marketing," she added.
"This Government must make it easier, cheaper and more appealing to buy healthier food and drinks, to help turn the tide on obesity."
Across England, 63.8% of adults aged 18 years and over were overweight or living with obesity in 2021-22. It has increased slightly year on year since the survey began in 2015-16.
About 25.9% of adults in the country were estimated to be living with obesity last year.
The British Obesity Society said there are "huge concerns" with the growing proportion of overweight adults in the country, but added it is not surprising.
They added the increasing cost of living has also increased consumption of processed foods as they are "quick, cheap and convenient".
The charity said there should be "more emphasis on fixing the food environment and making the healthy choice the easy choice".
They added the Government is introducing restrictions on where less healthy food is placed in supermarkets, calorie labelling on menus, alongside working to make it easier for people to make healthy food choices.
"Trials of new obesity treatments and technologies are being backed by £20 million of government funding, and we will introduce restrictions banning adverts on TV for less healthy foods before 9pm, as well as paid-for adverts of these products online," they said,
The figures also show that there a higher proportion of men were overweight or living with obesity (69.1%) than women (58.4%).