It all gets a little too scientific and ridiculous sometimes.  Not enough and too much sleep causes visceral fat, I’m sure eating the wrong foods and drinking alcohol also causes it.

Cyndi O’Meara

Lack of sleep in young ‘increases fat’

People under 40 who routinely sleep for five hours or less nightly are at increased risk of accumulating more abdominal fat.

US-based researchers have found a “clear association” between study participants who did not get enough sleep and the accumulation of visceral fat – fat around the organs – which heightens the risk of diabetes and heart disease.

“We don’t really know yet why this wasn’t seen in participants over 40,” said Dr Kristen Hairston, from the Wake Forest University School of Medicine.

“But it was clear that, in individuals under 40, it is worse to get five or less hours of sleep on average each night than it is to get eight or more hours.”

Over-sleeping was also found to be a more subtle cause of visceral fat accumulation, Dr Hairston said, while optimal amount of sleep was six to eight hours nightly.

Source: The Sydney Morning Herald, March 6 2010, http://news.smh.com.au/breaking-news-world/lack-of-sleep-in-young-increases-fat-20100306-ppa2.html