Study: Late bedtime for teens may lead to weight gain

We know getting enough sleep can also help prevent weight gain. But for teenagers, that may not be enough.

A new study shows just going to bed late can lead to putting on the pounds.

A new study from UC Berkeley finds if a teenager goes to bed late, around 11 p.m. or 12 a.m., they're at a greater risk for weight gain even if they get the recommended amount of sleep.

Researchers followed more than 3,000 young adults and found a late bedtime was associated with an increase in body mass.

So for a teenage-girl, 5'5, weighing 132 pounds and going to bed late from the period of adolescence to adulthood, the study found she'll gain 12 pounds.

But while the researchers say sleep duration and exercise did not make a difference, they do say fast food was a factor.

If you're going to bed late, you're more likely to reach for pizza or french fries than for a salad or other healthy option.