Being a few pounds overweight could extend life - and not shorten it, according to new research.
The findings will be greeted with relief by those who have indulged over the Christmas period. And they confound the widely-held medical belief that being overweight leads to an early grave.
US researchers analysed 97 studies involving nearly three million people, and found those classified as overweight were 6% less likely to die prematurely than those deemed to have a "healthy" weight.
They used the body mass index (BMI), which relates weight to height, to classify people into "recommended weight" (BMI 18.5-25), overweight (25-30), or obese (over 30).
Katherine Flegal, a statistician at the Centres for Disease Control and Prevention , said the lower risk of death in overweight people was consistent in the studies she looked at.
"Sometimes that surprises people but they really should not be too surprised, because in our categories of these 97 studies 80% of them showed that there was lower mortality in overweight than normal weight people,” she said.
Body weight only increased the risk of death when people passed a BMI of 35. At this point - morbid obesity - the risk increased by 29%, according to results published in the medical journal Jama .
The researchers only looked at mortality. Other studies have shown that overweight people are more likely to suffer from diabetes, heart disease and kidney problems.
Dr Flegal said better medical treatment may keep overweight people alive for longer. Alternatively, moderate amounts of body fat could protect the heart, she added.
But Tam Fry of the National Obesity Forum said it would be "catastrophic" if people use the research as an excuse to overindulge.
"The real fear is that people will take this to mean they can eat what they like," he said.
"If you are old, having a bit of extra weight can protect the body during periods of illness, and so on.
"But being obese is just as serious as it has always been. This research should not be a passport to cancelling the gym membership and eating black forest gateau."