Obesity is a greater burden on the UK's economy than armed violence, war and terrorism, costing the country nearly £47 billion a year, a report has found.
The study, commissioned by consultancy firm McKinsey and Company, revealed obesity has the second-largest economic impact on the UK behind smoking, generating an annual loss equivalent to 3% of GDP.
More than 2.1 billion people around the world - or nearly 30% of the global population - are now overweight or obese, with the figure set to rise to almost half of the world's adult population by 2030, according to the McKinsey Global Institute (MGI), which carried out the report.
It has now called for a "coordinated response" from governments, retailers, restaurants and food and drink manufacturers to address the "global obesity crisis".
A series of 44 interventions could bring 20% of overweight or obese people in UK back to normal weight within five to 10 years, the report said.
This would save around £16 billion a year in UK, including an annual saving of about £766 million in the NHS, according to the study.
The report said: "Obesity is a major global economic problem caused by a multitude of factors. Today obesity is jostling with armed conflict and smoking in terms of having the greatest human-generated global economic impact.
"The global economic impact of obesity is increasing. The evidence suggests that the economic and societal impact of obesity is deep and lasting."
The report found the economic impact from smoking in the UK was £57 billion in 2012, or 3.6% of GDP, while the country suffered a £43 billion annual loss from armed violence, war and terrorism or 2.5% of GDP.
In the UK, Government efforts to tackle obesity were "too fragmented to be effective", while investment in obesity prevention was "relatively low given the scale of the problem", the report said.
The UK spends less than £638 million a year on obesity prevention programmes - about 1% of the country's social cost of obesity, the study found.
But the country spends about £6 billion a year on the medical costs of conditions related to being overweight or obese and a further £10 billion on diabetes, it claimed.
Meanwhile, the cost of obesity and diabetes to the NHS is equivalent to the UK's combined "protection" budget for the police and fire services, law courts, and prisons, it added.
The current rate of obesity and overweight conditions suggest the cost to the NHS could increase from between £6 billion and £8 billion in 2015 to between £10 billion and £12 billion in 2030, the study found.
The recommended interventions to reduce the cost of obesity include:
:: Portion control in fast food packaged goods.
:: Investing in parental education.
:: I ntroducing healthy meals in schools and workplaces.
:: Changing the school curriculum to include more physical exercise.
:: Encouraging more physical activities by introducing bicycle lanes.
MGI director Richard Dobbs said: "Efforts to address obesity have been piecemeal up till now. Yet obesity is a systemic issue, born of many interlocking factors, and only a systemic response will do."
Dr Alison Tedstone, chief nutritionist at Public Health England (PHE), said: " Overweight and obesity is a complex problem which requires action across individual and societal levels involving industry, national and local government and the voluntary sector. There is no single 'silver bullet' solution.
"Today 25% of the nation is obese and 37% is overweight. If we reduce obesity to 1993 levels, where 15% of the population were obese, we will avoid five million disease cases and save the NHS alone an additional £1.2 billion by 2034.
"PHE will continue to support local authorities to provide effective weight management services, to influence the regulation of fast food outlets and provide healthier catering in hospitals and schools, which will all help people to lose weight."