Bad news for night owls: New study suggests going to bed after 2am leads to obesity

We've all heard the phrase "the early bird gets the worm", but it turns out if you're a night owl -  you might be eating more than your fair share. 

New research out of the Chinese University of Hong Kong has found going to bed late and having less than five hours of sleep a night could be increasing your risk of obesity. 

Over 130,000 participants were included in the analysis, with a bedtime of midnight or later characterised as "late night". 

A total of 19,660 participants (14.4 percent) had late bedtime behaviour. 

"Compared with a bedtime between 8pm and 10pm, late bedtime was associated with general obesity and abdominal obesity, particularly among participants who went to bed between 2am and 6am," the study reads. 

The findings suggest staying awake at night may suppress the secretion of melatonin which is associated with an increased risk of obesity, cardiovascular diseases and cancers.

And if you think you're countering that late night with a quick daytime nap, we've got further bad news.

The study also found longer daytime napping was associated with a higher risk of abdominal obesity, particularly among women - but the researchers suggest this could be because a daytime nap may occur more often due to a late night.

The results of this study echo those found in another article published in JAMA Internal Medicine last year, which used Fitbit wearable technology to collect sleep data from more than 120,000 people over a two-year period.

Participants with a BMI over 30 (considered the obesity range) had slightly shorter sleep durations and more variability in their sleep, they found.

"These findings provide further support to the notion that sleep patterns are associated with weight management and overall health. 

"The findings also support the potential value of including both sleep duration and individual sleep patterns when studying sleep-related health outcomes," the researchers wrote.