The epidemic — one-third of the world's population is overweight or obese in 2013, is costing Britain almost £47 billion a year, while globally, it is costing the world economy $2 trillion a year in health costs and lower productivity, according to a study from the McKinsey Global Institute (MGI).

Obesity ranks far more costly than alcoholism, climate change, air pollution and drug problems and falls just behind armed conflict and smoking in terms of the most costly human-generated burdens.

The financial loss to obesity is equivalent to Russia's gross domestic product (GDP).

In UK, obesity is second only to the £57 billion annual toll smoking takes on the economy.

MGI said, "Today obesity is jostling with armed conflict and smoking in terms of having the greatest human-generated global economic impact".

MGI said that obesity is a critical global issue that requires a comprehensive, international intervention strategy. More than 2.1 billion people — nearly 30% of the global population — are overweight or obese.

MGI said, "That's almost two-and-a-half times the number of adults and children who are undernourished. Obesity is responsible for about 5% per cent of all deaths a year worldwide and its global economic impact amounts to roughly $2 trillion annually or 2.8% of global GDP — nearly equivalent to the global impact of smoking or of armed violence, war, and terrorism".

"And the problem — which is preventable — is rapidly getting worse. If the prevalence of obesity continues on its current trajectory, almost half of the world's adult population will be overweight or obese by 2030,"

The MGI paper, "Overcoming obesity: An initial economic analysis," seeks to overcome hurdles by offering an independent view on the components of a potential strategy.

MGI has studied 74 interventions that are being discussed or piloted somewhere around the world to address obesity, including subsidized school meals for all, calorie and nutrition labelling, restrictions on advertising high-calorie food and drinks and public-health campaigns.

"We found sufficient data on 44 of these interventions. Existing evidence indicates that no single intervention is likely to have a significant overall impact. A systemic, sustained portfolio of initiatives is needed to reverse the health burden. In the UK, such a program could reverse rising obesity, saving the national health service about $1.2 billion a year," MGI 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.

The recommended interventions to reduce the cost of obesity include: Portion control in fast food packaged goods, investing in parental education, introducing healthy meals in schools and workplaces, changing the school curriculum to include more physical exercise and encouraging more physical activities by introducing bicycle lanes.