A new study has revealed that being overweight or slightly obese implies that you'll live longer on average than slim or skinny people.
A person who is overweight can expect to live two and a half months longer than someone of 'ideal' weight and 15 months longer than an underweight person, concludes the study of the relationship between body mass index (BMI) and longevity.
The study was conducted by actuarial mathematicians at Heriot-Watt University in Edinburgh.
The scientists found a link between being overweight and increased incidence of long-term ill health, although the difference is perhaps not as dramatic as many might expect.
Almost 55 percent of 70-year-old men of normal weight suffer high blood pressure, compared with 65 percent of men of the same age who are morbidly obese.
The Scottish Faculty of Actuaries commissioned the new research, which included examining databases in the UK and from the world-famous Framingham Heart Study, where 10,000 people shared their health data.
After reviewing the data, the researchers concluded that a 20-year-old man who was overweight or mildly obese on the BMI scale (25-40) would live on average to 78.8 years; an underweight counterpart (less than 18.5) will live to 77.5.
While the overweight live longer, they are more likely than lighter people to suffer from diabetes and high blood pressure. They are also more likely to get strokes and heart attacks.
"What the study makes clear is that obesity in itself - at least as it is measured by the BMI - is not as much of an indicator of life expectancy as many other factors, such as smoking," The Scotsman Howard Waters, professor of actuarial mathematics at Heriot-Watt University, as saying.
"It causes things such as diabetes and hypertension. These things in themselves do not actually kill, although they can contribute to other conditions that will kill, such as heart disease.
"However, it's not simple. Obesity and its effects will still need to be treated, in far more people, and the costs will be very considerable," Waters added.