It has been a well known fact that obstructive sleep apnea severity is directly correlated with weight gain or loss in adults. It's also why physicians often recommend weight loss as one of the ways to resolve obstructive sleep apnea (OSA). What has been less clear is exactly how weight influences sleep apnea until researchers at Univ of Pennsylvania examined the upper airway with MRI scans before and after weight loss. It is tongue fat!!! Researchers recruited 67 adult individuals…