Your sleeping habits can put you at risk of gaining weight.
For this article, I am citing four studies done in different population and different years which in one way or other point to one thing only. We should maintain good sleeping habits.
Sleeping Late could Lead to Weight Gain. 
Conducted by University of California – Berkeley, this study looked for relation between sleeping late and likelihood of weight gain in teenagers and adults.
It found that going to bed late during weekdays adolescence to adulthood is associated with an increase in body mass index over time.
It notice that teenagers and adults who go to bed late on weeknight are more likely to gain weight than their peers who sleep earlier.
The researchers analyzed longitudinal data from a nationally representative cohort of more than 3,300 youths and adults, and found that for every hour of sleep they lost, they gained 2.1 points on the BMI index over a five-year period.
[BMI or body mass index is the measure of a person’s weight in kilograms divided by the square of height in meters. A healthy adult BMI range is estimated to be 18.5 to 24.9]
This BMI increase was not mitigated by exercise, screen time, and the number of hours they slept did not mitigate according to the study published in the October issue of the journal, Sleep.
Thus adolescent bedtimes becomes a potential target for weight management during the transition to adulthood.
The study further mentions that adolescents who go to bed earlier will set their weight on a healthier course.
2. Early to Bed and Early to Rise Keeps Kids Leaner 
Published in September 2011, the study was conducted by American Academy of Sleep Medicine.
The researchers recorded sleeping time and waking up times of 2,200 Australian youths and found that night owls were at 1.5 times higher risk to become obese than the early birds. Not only this the who were late sleepers were twice as likely to be physically inactive and about 3 times more likely to sit in front of the screens [TV/computer/ video games] for more hours than guidelines recommend.
There was no difference in total sleep duration. Because the children who went to bed late, woke up late, and the children who went to bed early and woke up early. I mention this that less sleep is an independent parameter that determines the risk of being overweight and obese.
This study suggested that the timing of sleep is even more important.
The researchers noted that mornings are more conducive to physical activity than nights, which offer prime-time TV programming and social networking opportunities. This might explain sedentary This relationship between time of day and available activities might explain why more sedentary and screen-based behaviors were observed with later bedtimes.
Late Bedtimes and Less Sleep May Lead to Weight Gain in Healthy Adults 
This study was published in journal Sleep in July 2013 by American Academy of Sleep Medicine
This study included bed time and amount of sleep as parameters. It found that late bedtimes and chronic sleep restriction in otherwise healthy adults are more likely to gain weight
Study attributed the weight gain to increased increased consumption of calories during late-night hours, the period of additional wakefulness.
Till date this was considered as the largest, most diverse healthy sample.
The results showed that sleep-restricted subjects who spent only four hours in bed from 4 a.m. to 8 a.m. for five consecutive nights gained more weight than control subjects who were in bed for 10 hours each night from 10 p.m. to 8 a.m.
The study found an overall increase in caloric intake during sleep restriction due to an increase in the number of meals consumed during the late-night period of additional wakefulness.
The study also found that more fat was consumed in the night hours than during the day.
The study group comprised 225 healthy, non-obese individuals, ranging in age from 22-50 years.
Staying Up Late Night Carries Risk for Weight Gain 
Conducted by Northwestern University, this study from USA found that staying up late every night and sleeping as ahabit could put you at risk for gaining weight.
It was found that later sleepers ate more calories in the evening, more fast food, fewer fruits and vegetables and weigh more than people who go to sleep earlier and wake up earlier.
These people were also found to have a higher body mass index.
The extr calories were consumed during during dinner and later in the evening when everyone else was asleep.
The study was published online in the journal Obesity .
The study emphasized that human circadian rhythms in sleep and metabolism are synchronized to the daily rotation of the Earth, so that when the sun goes down you are supposed to be sleeping, not eating.
If sleep and eating are not aligned with the body’s internal clock, it can lead to changes in appetite and metabolism, which could lead to weight gain.
The study included 51 people (23 late sleepers and 28 normal sleepers) who were an average age of 30.
This study defined its early and late sleepers.
Late sleepers routine was
- Went to sleep at an average time of 3:45 a.m
- Awoke by 10:45 a.m.
- Ate breakfast at noon
- Lunch at 2:30 p.m
- Dinner at 8:15 p.m.
- Final meal at 10 p.m.
- Slept by 12.30 am
- Up by 8 a.m
- Breakfast by 9 a.m.
- Lunch at 1 p.m.
- Dinner at 7 p.m.
- Snack at 8:30 p.m.
There are many inference that could be drawn from these studies
There are three independent sleep related parameters that lead to risk of weight gain
- Time of sleep
- Amount of sleep
- Eating night time snacks
You Should Sleep Early
Your body is not used to sleeping late and wants to sleep early. If the body gets out of this alignment, it is subjected to certain metabolic changes which makes you prone to gain weight.
You Should Sleep for the Required time
There should not be a chronic sleep deficit. One should take full time required sleep. The requirement of sleep varies from person to person but most of people require 7-9 hours of sleep.
Avoid Late Night Snacks
Even if you feel like taking snacks, take those lower in calorie. Keep fruits and other stuff in the house and avoid eating high fat diet.
So the Benjamin Franklin was right
Early to bed and early to rise………..
- Lauren D. Asarnow, Eleanor McGlinchey, Allison G. Harvey. Evidence for a Possible Link between Bedtime and Change in Body Mass Index. SLEEP, 2015; 38 (10): 1523 DOI: 10.5665/sleep.5038
- Tim S Olds, Carol A Maher, Lisa Matricciani. Sleep duration or bedtime? Exploring the relationship between sleep habits and weight status and activity patterns. Sleep, 2011.
- Andrea M. Spaeth, David F. Dinges, Namni Goel. Effects of Experimental Sleep Restriction on Weight Gain, Caloric Intake, and Meal Timing in Healthy Adults. SLEEP, 2013; DOI: 5665/sleep.2792
- Kelly G. Baron, Kathryn J. Reid, Andrew S. Kern, Phyllis C. Zee. Role of Sleep Timing in Caloric Intake and BMI. Obesity, 2011; DOI: 1038/oby.2011.100