This figure could rise to almost £33 billion a year by 2025 if current health trends continue.
The study calculated immediate and long-term potential savings to individuals and the public purse if obesity rates stop rising; if the 26% of smokers who attempt to quit each year are successful; and if excessive drinkers bring their intake down to recommended levels.
According to the findings, making healthier lifestyle choices such as quitting smoking, reducing alcohol intake and becoming more active can have an immediate impact on people's wallets.
Smokers who successfully quit will find, on average, an extra £1,555 in their pocket at the end of the year. If they quit between the ages of 30 and 49 they could enjoy an average additional income of £7,186 per annum in middle age, due to increased life expectancy.
Excessive drinkers who commit to drinking within the Government's recommended daily allowance will save an average of £200 a year on alcohol expenditure.
People suffering from obesity could reduce their future earning power by as much as £500 per annum because qualifications, skills and experience become out-dated during long-term absences from work caused by their conditions.
By 2025, if healthier lifestyles are adopted, the total savings made by individuals alone across the UK could amount to £22 billion a year, two-thirds of the potential annual savings of £33 billion.
The £22 billion comes from savings of £5 billion and £3.9 billion through reduced expenditure on alcohol and cigarettes respectively and £7.4 billion saved in additional earning potential due to increased life expectancy from quitting smoking. Individuals could also save £1.7 billion through increased employment and £3.9 billion through increased earning potential due to a fall in obesity levels. The findings of the report also outline the long-term financial benefits of healthier lifestyles to employers and the NHS, which make up the remainder of the £33 billion figure: UK employers could save close to £3 billion a year (£2,737 million) by 2025: They would enjoy immediate savings from increased productivity and decreased sick pay of almost £1.8 billion per year lost through alcohol misuse. This figure would rise to almost £2.2 billion (£2,186 million) by 2025, plus £61 million a year lost through absences caused by smoking-related illnesses. A further £490 million a year would be saved by 2025 on obesity-related conditions.
The NHS could save £8.2 billion a year by 2025: Some £2 billion (£1,958 million) would be saved instantly through reduced numbers of accidents and emergencies resulting from excessive drinking, £5.8 billion a year by 2025 through reduced costs from alcohol-related medical conditions and a further £1.9 billion and £575 million a year through the treatment of obesity and smoking-related illnesses respectively.
Johann Carinus, assistant medical director, Bupa Health and Wellbeing, said: "This study not only reveals the true cost to the nation of unhealthy lifestyle choices, but it also highlights the considerable savings to the public purse which could be achieved through individual commitments to health improvement. "Data released earlier this year from the Bupa 'Health Age' report showed that almost 70% of people in the UK wanted to make a positive change to improve their health in 2011. While ultimately it is up to individuals to make healthy lifestyle choices, there is a huge opportunity for healthcare providers and employers to play their part in empowering individuals to live more healthily. The benefits for everyone are clear." To coincide with the new findings, Bupa is launching the 'Bupa health pledge' campaign, calling on the public to make a pledge to achieve their health goals - whether it is to quit smoking, cut down on alcohol, eat more healthily or do more exercise.