There is an association between short sleep duration and increased risk for obesity, increased energy intake, greater percentage of body fat and weight gain over time.
In addition to duration, poor sleep quality such as disruption of slow wave sleep or sleep fragmentation due to obstructive sleep apnea, has been associated with a metabolic dysregulation .
Being awake late at night may be related to social and environmental factors that place individuals at greater risk for obesity via an increase in the opportunity to consume calories (greater caloric intake, more frequent fast food consumption, lower fruit and vegetable consumption, greater soda and caffeine consumption) and poor availability of healthful foods at night.
Consuming calories in the evening is associated with a higher BMI.
As a conclusion, sleep duration is linked to obesity and there is a relationship between the timing of feeding and weight regulation.