Not familiar with the obesity paradox? Read about it at Wikipedia, which may or may not be accurate.
From a recent article at MPT:
“A massive meta-analysis pooling data from millions of people in several countries reaffirmed that body mass index (BMI) has a J-shaped relationship with mortality, with the lowest death rates among those in the traditional “normal” range of 20-25.
The study of nearly four million people revealed that those in every BMI category above and below the normal range had significantly higher mortality rates.The elevation in risk applied to even mildly overweight people, and was highest for those with overt obesity, according to researchers with the Global BMI Mortality Collaboration, a part of the University of Cambridge.”
“Our results challenge recent suggestions that overweight and moderate obesity are not associated with higher mortality, bypassing speculation about hypothetical protective metabolic effects of increased body fat in apparently healthy individuals,” wrote the authors. Their data showed the J-shaped relationship maintained for every age group, albeit attenuated somewhat among those in the 70-89 age range.”