Courtney Peterson, PhD, MSC, is assistant professor in the Pennington Biomedical
Research Center's Skeletal Muscle Physiology Laboratory. She is one of four CCTS Mentored
Career Development Program (KL2) awardees for 2016. Peterson said she learned about
the award opportunity from her center's director, Dr. William Cefalu. Prior to applying
for the K award, Peterson had participated in a CCTS Panel for an NIH-funded K award
application.
"I had gotten very helpful feedback on that," she says. "I changed the scope of the application significantly, but this award is on very similar research."
Peterson's K award tackles, "Meal Timing Affects on Circadian System in Humans," looking at how meal timing affects health, in particular, energy balance and the circadian clock.
Three to four years ago, Peterson says she learned of animal studies suggesting that grazing, or eating throughout the day, may not be beneficial for health, and that in fact eating early on in the day in a very narrow time period might be beneficial. The studies looked at two groups of rodents-one which ate only within an 8-hour period, and one which ate all day long-and the grazing group burned fewer calories relative to body weight each day.
"I thought this was absolutely fascinating," Peterson recalls. What she thinks might be happening in these studies is:
1) By having a longer fasting period each day between dinner and breakfast, the body has a longer repair period, which may lower levels of oxidative stress as well as allow time for reparative processes.
2) By eating early in the day, we may be taking advantage of eating at the best time as determined by circadian rhythms-optimal times where your body is best at doing certain things (for example, testosterone levels are highest at the morning; sleep is best at night). Blood sugar control is better during the morning, she says, and starts to decline during the afternoon and evening.
"I wanted to see what happened when people eat their dinner super early in the day," Peterson says, "and see how eating earlier relative to the time when you go to sleep affects the body."
She's conducting two pilot studies looking at eating early in the day, one taking men with prediabetes and having them test both eating early in the time (time-restricted feeding) and grazing.
"We're primarily looking at what it does to their blood sugar control," she says.
The second study looks at overweight men and woman and tests how grazing versus time-restrictive diets affect how many calories they burn-they spend 24 hours in a respiratory chamber. She plans to look at metabolic hormones to determine if they might be related to changes in the body's internal clock.
In the training and career development portion of her KL2, Peterson plans to do a 10-week training session with Frank Scheer, PhD, who holds joint appointments at Brigham and Women's Hospital and Harvard Medical School. "He does clinical research on circadian rhythms, sleep, and meal restrictions, so I'll be training with him on standardization [of circadian studies]." Additional training will take place with Karen Gamble, PhD, with the UAB Nutrition and Obesity Research Center, to learn about molecular and animal model techniques.
"The biggest thing that was helpful for me from the application process for the KL2 was all of the feedback, and the support and mentoring resources. Going through the process and helped me articulate the kind of research I want do," she says.