Is sleep the missing factor for weight management?

As most health professionals who work in the weight management field already know, the simple advice of "eat less, exercise more" is far removed from the complicated answer to weight loss. New research suggests there is another major fact that can influence your risk for gaining weight and it has nothing to do with how much or little exercise you do or food you eat (well...at least not directly related...): SLEEP.
We all know that lack of sleep is detrimental to our health but does it influence our weight?

Apparently, for adults, if you sleep less than 6 hours a night, your risk for being obese is raised by a factor of 3.8 (compared to adults who slept 7-8hrs) and in one study, this was the greatest impact on the participants' weight. Other impacts on weight included a high dis-inhibition behavior (one meaning is interpreted as overeating in response to external cues, or cues not related to hunger. External cues include other people eating or ads on TV), low calcium intake and high hunger behavior.
Other studies have shown that over 9hrs of sleep are also associated with more likelihood of weight gain. Therefore, it is recommended that adults aim for 7-8hrs of sleep per night.

However, if you were thinking about catching up on sleep a few nights of the week while skimping on other nights, think again. Other studies have shown that when you are sleep deprived (say 4hrs of sleep), your body produces hormones and signals that increase hunger and appetite. One study showed that the sleep deprived participants ate 559 more calories the day following 4hrs of sleep.

Sleeping less increases hormones that increase hunger and appetite, not to mention that when you are awake longer you have more opportunity to eat AND if you are tired, you are less likely to exercise.
So if you are trying to lose weight keep in mind that sleeping fewer than 7 hours can impact compliance to a lower calorie diet! And if you are trying to maintain your weight, increasing sleep to 7-8hrs per night can limit fat gain over time.

References: 
Brondel et al. Am J Clin Nut (2010)
Chaput et al. Int. J Obes (2011)(2006)
Chaput and Tremblay. Physiol Behav (2007)
Tremblay, Mathieu, Chaput. Obesity (2009)
Spiegel et al. Lancet (1999)
Spiegel et al. Ann Intern Med (2004)
Chaput et al. Sleep (2008)
Chaput et al. Obesity (2009)
Arlet et al. Ann Intern Med (2010)
Schmid et al. Am J Clin Nut (2009)