WASHINGTON: Being slimmer could be as simple as waking up early for some morning sunshine, U.S. researchers suggested Wednesday.
A small study of 54 volunteers showed that the leanest ones did not necessarily eat better or exercise more than the rest. They simply were exposed to more bright daylight earlier in the day.
The findings by Northwestern University researchers are published in the journal PLOS ONE.
“The earlier this light exposure occurred during the day, the lower individuals’ body mass index,” said co-lead author Kathryn Reid, research associate professor of neurology at Northwestern University Feinberg School of Medicine.
“The later the hour of moderately bright light exposure, the higher a person’s BMI.”
Participants’ average age was 30. They wore wrist monitors to measure their light exposure and sleep cycles and kept food logs for the duration of the seven-day study.
Morning light was found to have an influence on body mass, regardless of a person’s physical activity level, caloric intake, sleep timing or age.
The study found morning light accounted for about 20 percent of a person’s body mass index.
As little as 20 to 30 minutes could be enough to affect BMI between 8 a.m. and noon, the study said.
A version of this article appeared in the print edition of The Daily Star on April 04, 2014, on page 13.