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Exposure to morning light may help you slim down, according to a new study.

New research conducted at Northwestern Medicine has for the first time linked timing, intensity and duration of a person's light exposure during the day to their weight.

The study revealed that people who had most of the daily exposure to even moderately bright light in the morning were thinner than those who had most of their light exposure later in the day.

"The earlier this light exposure occurred during the day, the lower individuals' body mass index," investigator Kathryn Reid, research associate professor of neurology at Northwestern University Feinberg School of Medicine, said in a news release. "The later the hour of moderately bright light exposure, the higher a person's BMI."

The findings held true even after researchers accounted for physical activity level, caloric intake, sleep timing, age or season.

The study revealed that 20 percent of a person's body mass index was influenced by their exposure to morning light.

"Light is the most potent agent to synchronize your internal body clock that regulates circadian rhythms, which in turn also regulate energy balance," study senior author Phyllis C. Zee, M.D., said in a news release. "The message is that you should get more bright light between 8 a.m. and noon."

Researchers noted that 20 to 30 minutes of morning light is enough to influence a person's body mass index. However, the exact mechanism of how light influences body fat is still unknown.

"If a person doesn't get sufficient light at the appropriate time of day, it could de-synchronize your internal body clock, which is known to alter metabolism and can lead to weight gain," Zee said.

"Light is a modifiable factor with the potential to be used in weight management programs," Reid said. "Just like people are trying to get more sleep to help them lose weight, perhaps manipulating light is another way to lose weight."

The latest study involved 26 males and 28 females with an average age of 30. Participants wore a wrist actigraphy monitor that measured their light exposure and sleep parameters for seven days. Participants' caloric intake was measured based on seven days of food logs.

Researchers said the latest findings highlight the importance of circadian health, in which exposure to light and dark is synched with your internal body clock.

"We focus on how too much light at night is bad; it's also bad not to get enough light at the appropriate time during the day," Zee said.

"This is something we could institute early on in our schools to prevent obesity on a larger scale," Zee added.

The findings are published April 2 in the journal PLOS ONE.