Data released by Public Health England shows the number of adults who are overweight or obese across the three districts are above the national average.
The Active People Survey, which was collected by Sport England, was launched as part of Public Health England's mission to protect and improve the nation's health and address inequalities through working with national and local government, the NHS, industry, and the voluntary and community sector.
The shock figures come after the Daily Echo launched its Staying Alive campaign, which urges people to take active steps to overhaul their diet and fitness regimes to prevent the likelihood of a premature death.
The survey revealed a total of 64.8 per cent of people in Southampton are overweight or obese, while that figure increased to 68.6 per cent in the New Forest.
In Eastleigh, a total of 67.9 per cent of the population are overweight or obese.
The national average by local authority is 63.8 per cent.
Hampshire came 14th highest out of 27 county councils with 65.1 per cent of people overweight or obese, but came out as the fattest authority the Wessex region.
Public Health England says the figures, which were collected in 2012, are “worryingly high” and an overweight or obese population can be influenced by a variety of factors including social and economic deprivation and age.
The health body stressed people who are overweight or obese have an increased risk of developing type 2 diabetes, heart disease and certain cancers.
It determines if people are overweight or obese using the body mass index (BMI), which is calculated using a person's weight and height.
The obesity crisis costs the NHS £5.1b a year, according to the National Audit Office (NAO), and affects a person's ability to work and their underlying mental health.
A spokesman for Eastleigh Borough Council said it encourages its people to use a wide range of facilities to lead an active lifestyle.
They said: “The council is committed to encouraging its residents to lead an active and healthy lifestyle.
“We encourage local people to use the wide range of local facilities that we provide including country parks, leisure centres, dance facilities and open spaces to become more active and improve their health”.
Dr Jim O'Brien, Wessex Public Health England centre director said: “Public Health England is committed to helping tackle the levels of people who are overweight and obese in Wessex by supporting our local authorities to develop a broad programme of action to reduce levels of excess weight.
“There is no silver bullet to reducing obesity. It is an issue that requires action at national, local, family and individual level. Local authorities are ideally placed to develop co-ordinated action across their departments, services and partner organisations to tackle overweight and obesity in the local population.
“This new data will enable local councils to monitor progress towards the national ambition of achieving a downward trend in excess weight by 2020. Today's information will help local authorities to understand the extent of the problem in their area and support their on-going efforts to tackle overweight and obesity and improve the health of their local population.”
The amount of people overweight per local authority by percentage:
- Gosport 72.9%
- New Forest 68.9%
- Eastleigh 67.9%
- Hampshire 65.1%
- Isle of Wight 64.9%
- Southampton 64.8%
- Fareham 64.8%
- Winchester 58.5%
- Portsmouth 57.9%
How to work out if you are overweight or obese:
Public Health England used the body mass index (BMI) to determine if a person is overweight or obese.
It is determined by a person's height in ft and inches, and weight in lbs or kgs.
A person's weight is then divided by their height, and then divided by height again to get a BMI score.
People exceeding a BMI number of 25 are overweight.
The health body says obesity among adults increased sharply during the 1990s and 2000s.
By 2050 it is estimated the prevalence of obesity will affect 60 per cent of adult men and 50 per cent of adult women.
The prevalence of obesity among adults has increased sharply during the 1990s and early 2000s.
The proportion who were categorised as obese (BMI 30kg/m2 or over) increased from 13.2% of men in 1993 to 24.4% in 2012 and from 16.4% of women in 1993 to 25.1% in 2012 (HSE).
By 2050 the prevalence of obesity is predicted to affect 60% of adult men, 50% of adult women.
However BMI is limited, as those with a high muscle percentage such as personal trainers, weight lifters or professional athletes, can be erronesously classfied as obese due to muscle weighing more than fat.