Much ink has been spilled about studies detailing the health risks associated with being overweight.

And while there is no doubt that severe obesity can lead to a litany of medical problems, a new study suggests that moderately overweight people are still pretty healthy. So, what's the skinny on this phenomenon?

In fact, a new report from the University of California Davis School of Medicine has found that being underweight is much more likely to kill you than carrying a few extra pounds.

To reach this conclusion, researchers tracked 51,000 Americans of all ages over six years.  They discovered that those with a Body Mass Index [BMI] under the norm were twice are likely to have died than those who fall in the normal range of weight. "Severely" obese people only have a death rate 1.26 times the normal.

"There is currently a widespread belief that any degree of overweight or obesity increases the risk of death, however our findings suggest this may not be the case. In the six-year timeframe of our evaluation, we found that only severe obesity was associated with an increased risk of death" said Prof. Anthony Jerant, who worked on the study.

Underweight people, it seems, are at a much greater risk of death.

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