Obesity tied to risk of psychiatric disorders

How's this possible?

"Obesity is a well known risk factor for certain physical health problems, but a new study suggests that heavy adults also have higher rates of psychiatric disorders.

Using data from a national health survey of more than 40,000 Americans, researchers found that obese adults were up to twice as likely to suffer from depression, anxiety and other mental health conditions as normal-weight adults."

What could fat people who huff and puff at the slightest exertion, wear muumuus, need special equipment just to clean themselves and wipe their butts and require ton-tested toilets just to go potty be depressed or anxious about?

A real mystery.