Obesity could cost Scotland as much as £4.6 billion a year, according to a new report.

A briefing produced by the Scottish Parliament Information Centre (SPICe) said while estimates of the economic impact of the problem vary, the "key message" is that overweight and obese people "place a significant and growing burden on NHS Scotland and the Scottish economy as a whole".

Figures from 2013 show almost two thirds (64.6%) of adults were overweight, with 27.1% classed as being obese.

The paper said the annual cost to the health service in Scotland may be "as much as £600 million".

But it added that when other factors are included in the calculations, the "estimates of the total economic costs of obesity to Scotland range from £0.9 billion to £4.6 billion per year".

The £4.6 billion estimated total cost is based on research by the McKinsey Global Institute, which last year put the global economic impact of obesity as 2 trillion US dollars (£1.3 trillion) - only slightly less than the 2.1 trillion US dollar (£1.4 trillion) estimated cost of both smoking and armed violence, wars and terrorism.

That research took into account the loss of productivity due to people dying earlier or having poorer life quality because of their weight, direct healthcare costs and the amount of investment needed to mitigate the impact of obesity.

It suggested the cost of obesity in the UK as being equivalent to 3% of GDP, with the SPICe report adding that "converting their estimate from dollars to pounds, and adjusting pro rata to Scotland's population size, results in a figure of £4.6 billion".

The report added: "Although the estimates vary, the key message is that overweight and obesity together place a significant and growing burden on NHS Scotland and the Scottish economy as a whole."

Scottish Conservative health spokesman Jackson Carlaw said: "It's becoming increasingly apparent that obesity is rivalling almost everything else when it comes to a public health challenge.

"We need to treat it as seriously as we have done alcohol and cigarette addiction.

"However, while the NHS and Scottish Government can always do more, in general it comes down to an issue of personal responsibility, and we mustn't forget that."