NCATS-Supported Study Shows Eating Before 3 p.m. Can Improve Health

Courtney Peterson, Ph.D., measures a participant’s body mass and fat with a DEXA scan.

Courtney Peterson, Ph.D., measures a participant’s body mass and fat with a DEXA scan. (University of Alabama at Birmingham Photo)

Fasting for certain periods during the day can help people lose weight, which may lead to additional health benefits such as lowering blood pressure and diabetes risk. It was not known previously whether weight loss through fasting was directly related to these other health benefits.

That connection is now clearer based in part on the work of investigators supported through the NCATS Clinical and Translational Science Awards (CTSA) Program hub at the University of Alabama at Birmingham (UAB). Through a small, rigorously controlled trial, the research team found that eating all meals by midafternoon and fasting the rest of the day can improve blood pressure and insulin sensitivity, even without weight loss. The results are reported in Cell Metabolism.

The investigators tested a type of intermittent fasting that involves eating all meals within a six-hour window before 3 p.m. Eight men with prediabetes followed this schedule for five weeks. They later switched to the typical American meal schedule, where they ate the same number of calories spread over 12 hours.

“Our proof-of-concept trial is the first clinical trial in humans to show that intermittent fasting’s benefits are not simply due to eating less or losing weight,” said Courtney Peterson, Ph.D., an assistant professor at UAB, who led the study. “It points to the benefits of daily fasting as well as eating early, which puts you in sync with circadian rhythms in metabolism.”

Eating in sync with circadian rhythms — which are daily 24-hour rhythms that arise from our body clock — promotes better blood sugar control and greater energy expenditure in the morning, suggesting this is the optimal time to eat. Peterson plans to tease apart the effects of fasting versus circadian timing in upcoming clinical trials in her laboratory.

Peterson was a scholar in NCATS’ CTSA Program Mentored Clinical Research Scholars (KL2) training program, which supported the study. Learn more about Peterson’s experience as a KL2 scholar.

Posted August 2018