To shine a little light on the subject of circadian rhythms and maintaining a health body weight, a recent study published by Northwestern University researchers found that folks who had exposure to light in the morning were most likely to have a lower body mass index (BMI), regardless of how many calories they ate, their activity levels, or how long they slept.
The early morning hours provided the most benefit. BMI rose by 1.28 points for every hour that light exposure was delayed. (Even with BMI being thought of as a flawed measure, other research supports light exposure for weight management.)
The researches recommendation: people should try to get light exposure between 8 AM and noon for about 20 to 30 minutes. Sounds like a morning walk should be right up our alley.