A recent study which suggested that being overweight can lead to a longer life has caused controversy among obesity experts.
One expert labelled the findings a "pile of rubbish" while another said it was a "horrific message" to put out, the BBC reported.
The study, which has been in the Journal of the American Medical Association, suggested that the overweight people were less likely to die prematurely than people with a "healthy" weight.
The researchers at the US National Centre for Health Statistics looked at 97 studies involving nearly 2.9 million people to compare death rates with Body Mass Index (BMI) - a way of measuring obesity using a person's weight and height.
A healthy BMI is considered to be above 18.5 and below 25. However, overweight people (with a BMI between 25 and 30) were 6 percent less likely to die early than those considered to have a healthy weight, the study reports.
According to the study, being "overweight was associated with significantly lower all-cause mortality".
Possible explanations included overweight people getting medical treatment, such as to control blood pressure, more quickly or the extra weight helping people survive being severely ill in hospital.
However, the researchers point out they looked only at deaths and not years spent free of ill-health.
On Tuesday, the Royal College of Physicians called for the UK to rethink the way it tackles obesity.
Prof John Wass, vice-president of the college, said that the largest people will have died years before and pointed to health problems and higher levels of Type 2 diabetes.
On the other hand, other experts criticized the research methods.
Donald Berry from the University of Texas said that some portion of those thin people are actually sick, and sick people tend to die sooner, while Dr Walter Willett from the Harvard School of Public Health said that the findings of the study are an even greater pile of rubbish than a study conducted by the same group in 2005.