We are living longer despite getting fatter, and there is no sign yet that the increase in life expectancy is coming to an end, according to a study.
A baby born today in the West can look forward to between six and eight years of extra life compared with one born in 1970. Moreover, Britons are outliving Americans, despite the US having a higher national income and the highest spending on healthcare.
Some doom mongers have warned that today's children could be the first to die sooner than their parents because of the global explosion in obesity, but researchers say life expectancy is increasing in almost all European countries for the first time in decades.
But obesity has also been rising in the UK, from 7 per cent of adults in 1980 to 23 per cent in 2009. Rates are even higher in the US. Obesity is known to increase the risk of heart disease, cancer, Type 2 diabetes and high blood pressure – so why is life expectancy not declining?
Professor David Leon, an expert on population health at the London School of Hygiene and Tropical Medicine, who analysed the figures in the International Journal of Epidemiology, said: "There is a tendency for people to talk about things going wrong. But it is important the public are made aware that, so far, things are going right."
However, he warned there was no room for complacency and that many important questions remained about the drivers of the trends – such as the decline in smoking since 1970 and the fact heart disease deaths have fallen faster in the UK than in any other western European country.
But a little extra weight might also be good for you. Professor Leon said: "If you get poorly you lose weight. So if you fall sick it may be better if you have got something in reserve to call on."
A study by Katherine Flegal, published in the Journal of the American Medical Association in 2007, suggested fitness, not fatness, was the key determinant of longevity. Those who were overweight, smoked, ate junk food and took no exercise were heading for an early grave – all factors which increased the risk of heart disease and cancer.
But for those who were a little chubby but had a healthy lifestyle, the outlook was rosier. They were more likely to die of some conditions, such as kidney disease and diabetes, but less likely to die from lung diseases.
Overall, people who were overweight had a lower mortality rate than people who were underweight, obese or normal.
However, Professor Leon warned that quality of life was just as important.
For example, diabetes is soaring and destroys the eyes and the circulation, leaving victims blind and limbless (through amputation) before they die.
"It may be that we are holding off the fatal consequences of diabetes with better treatment," he said. "But there are huge consequences in terms of the burden on the health service – patients have to take a lot of pills and face a lot of complications."