Sleep is as important as diet and exercise in efforts to maintain a healthy weight in childhood.
The recently formed public health advocacy group, the Sleep Health Foundation, argues that sleep is often ignored in the obesity debate.
''We have hard data about lack of sleep causing obesity,'' said its founding member, David Cunnington, also a physician at the Melbourne Sleep Disorders Centre.
''We need a public health message which promotes sleep as well as diet and exercise. Diet and exercise are on the radar in a public health sense but people see sleep as a thing you can cheat, as something you don't need to respect. It's not just overlooked, it is ignored.''
Adolescents are at higher risk of sleep deprivation due to a phenomenon health experts dub ''infomania'', or the compulsive desire to check email, text messages and social media sites at the expense of a good night's rest.
Diet and exercise are on the radar in a public health sense but people see sleep as a thing you can cheat, as something you don't need to respect. It's not just overlooked, it is ignored.
International research suggests that electronic media is far more disruptive to sleep than caffeine, said Chris Seton, a sleep specialist at The Children's Hospital at Westmead. It is having a direct impact on the weight of both children and adolescents.
''The so-called obesity epidemic is paralleled by the sleep deprivation epidemic,'' Dr Seton said. ''There are more and more kids coming forward presenting with both problems.''
Dr Cunnington also points out that the growth in so-called energy drinks has been driven by a switched on, sleep-deprived youth culture. ''The energy drink industry, which is arguably targeted towards adolescents, has sprung up in line with growth in use of electronic media,'' he said.
Getting enough sleep - between 10 and 12 hours a night for children and adolescents - is one of the ''super seven'' strategies for weight maintenance recommended by The Children's Hospital.
Sleep deprivation affects the hormones that control appetite, with a tired person likely to eat more.
''If you are sleep deprived the hormones which make you eat more get up-regulated and the hormones which suppress your eating get down-regulated,'' Dr Seton said.
''It was previously thought that it was just psychological, that if you are tired you are more likely to eat, which is true to an extent. But it's really the hormonal connection which plays a bigger role.''
Adolescents are prone to sleep deprivation as they tend to be the most engaged with electronic media. A study of 12,000 adolescents by the US National Sleep Foundation in 2011 found that 92 per cent of teenagers do not turn their mobile phones off at night. Three-quarters of teens who wake during the night will use electronic media.
''The data about the adolescents is frightening,'' Dr Seton said. ''The impact of electronic media late at night is extraordinary. We always knew it had an impact on sleep but the size of the impact is quite scary.
''We used to think that caffeine was the big issue with kids and sleep but all the research suggests that the impact of caffeine is minimal compared with electronic media. Electronic media is far worse.''
Dr Seton believes there is a case for schools starting at a later time to offset the lack of sleep suffered by teens. The idea has been introduced in some US states with positive results.
''We have approached the [NSW] government [in 2011] about doing a trial into late school starting times here but whenever we mention it, it gets brick-walled a bit,'' he said.
In the meantime, Dr Seton said, adolescents needed to be encouraged to recognise the importance of sleep for weight maintenance as well as for overall physical and mental health.
''Teenagers just don't see sleep as being particularly important - it is a perception issue,'' he said.
Younger children can develop good sleep behaviours through routine, said Gerri Minshall, weight management clinical psychologist at The Children's Hospital.
She recommends limiting electronic media in the evenings and putting children to bed at a regular time each night.
''I know that can be difficult in our time poor society but the benefits are worth it,'' she said. ''Have a screen lock-down period for an hour before bedtime and follow the same routine each night so the child knows what to expect and it becomes a habit.''
The hospital supports The Sun-Herald's childhood obesity campaign, Healthy Habits, aimed at giving parents practical strategies to help deal with the epidemic.
Good night tips
- Children and adolescents need 10 to 12 hours of sleep each night.
- Parents should make sure children do plenty of physical activity during the day.
- Have a set bed time every night, including weekends.
- Switch off all electronic devices one hour before it is time for bed.
- Do not have a television or game console in the bedroom.
- Make sure older children switch off their phones before bed.
Source: The Children's Hospital at Westmead; Sydney Children's Hospital; Kaleidoscope - Hunter Children's Health Network.