Brits top the league table of and experts fear that soon we'll be dealing with all the supersize problems that come with it.
The concern is that by 2020 a quarter of our children will be clinically obese, that by 2050 we will be spending £32 bn a year treating obesity-related illnesses as we face a 20 per cent rise in heart disease and a staggering 70 per cent rise in type 2 diabetes.
And those experts point the finger of blame firmly at our continuing consumption of junk foods.
They're now making the case for government moving beyond suggesting we remember our and take a greater role in dealing with our ever-expanding waistlines.
So Panorama is asking whether it's time to tax the fat?
Would putting up the price of junk food - with its high sugar and fat content - cut these rising obesity rates in the same way as a tax on cigarettes - vigorously contested by the tobacco industry at the time - has helped reduce smoking?
In 'Tax the Fat', Panorama delves into the rich archive to take the viewer back to a time when the link between human behaviour and ill-health was still a matter of conjecture - as shown by this Ministry of Health report that smoking might cause lung cancer.
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In the end of course, the link between smoking and ill-health was universally accepted and measures gradually introduced to combat smoking rates.
The debate about obesity has been going on just as long but without reaching a solution, as this Panorama, broadcast on 10 April 1967 shows.
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Rather depressingly, the sequence shows how little has changed in the past 40 years apart, perhaps, from those expanding wasitlines and a growing campaign for a 'fat tax'.
Supporters of a 'fat tax' point out it would have the added benefit of boosting the coffers of the Treasury and help fund the cost of treating obesity-related illnesses.
This particular battle of the bulge is just as likely to be fiercely contested. A proposal to tax sugary drinks in the US has met with well-funded and vigorous opposition from those in the industry.
Anti-poverty campaigners in the UK too are concerned that such a tax would hit the poorest in the population - often the highest consumers of these products - hardest.
Even if a fat tax was introduced in the UK, in The Lancet medical journal has suggested that a fat tax alone might not even be enough to halt the problem. It recommends combining the tax with limits on junk food advertising and better labelling on foods.
So is this necessary action to stop a healthcare time-bomb or ?
As Panorama explores this contentious issue, let us know what you think by leaving your comment here.