BYU Releases Study on Late-Night Snacking

Contributed By Ryan Morgenegg, Church News staff writer

  • 10 July 2015

Researchers at Brigham Young University have shed new light on why people who snack at night don’t get the same “food high” as they do during other times of the day.  Photo by Jaren Wilkey, BYU.

Article Highlights

  • BYU researchers used functional MRI to monitor the brain to measure how it responded to high- and low-calorie food images at different times of the day.
  • The participants viewed 360 images during two separate sessions held one week apart—one during morning hours and one during evening hours.
  • Morning MRI scans were performed between 6:00 and 9:00 a.m. and the evening scans between 6:00 and 9:00 p.m.

“You might overconsume at night because food is not as rewarding, at least visually, at that time of day. It may not be as satisfying to eat at night, so you eat more to try to get satisfied.” —Travis Masterson, lead author of the study at BYU

PROVO, UTAH

Researchers at Brigham Young University have shed new light on why people who snack at night don’t get the same “food high” as they do during other times of the day.

“People eat at night for a variety of reasons that often have little to do with hunger, from satisfying cravings to coping with boredom or stress,” states the website webmd.com. “And after-dinner snacks tend not to be controlled. They often consist of large portions of high-calorie foods like chips, cookies, and candy eaten while sitting in front of the television or computer.”

“You might overconsume at night because food is not as rewarding, at least visually, at that time of day,” said Travis Masterson, lead author associated with the study at BYU. He is working toward a master of science degree in exercise science. “It may not be as satisfying to eat at night, so you eat more to try to get satisfied.”

In order to understand the scientific aspects of late-night snacking, BYU neuroscientist Brock Kirwan and other researchers used functional MRI to monitor the brain to measure how it responded to high- and low-calorie food images at different times of the day. The participants viewed 360 images during two separate sessions held one week apart—one during morning hours and one during evening hours. Morning MRI scans were performed between 6:00 and 9:00 a.m. and the evening scans between 6:00 and 9:00 p.m.

The study shared details that subjects looked at images of both low-calorie foods such as vegetables, fruits, fish, and grains and high-calorie foods such as candy, baked goods, ice cream, and fast food. As expected, the researchers found greater neural responses to images of high-calorie foods. However, they were surprised to see lower reward-related brain reactivity to the food images in the evening.

“The simple fact that there is a difference based on time tells us something important,” said Brother Masterson. “Different times of the day can affect how we react to our environments and can play a factor into our daily behaviors. Being aware of this can help us to realize when we are being influenced or affected and allow us to make positive changes.”

The study appears in the academic journal Brain Imaging and Behavior and also reports that participants were subjectively more preoccupied with food at night even though their hunger and “fullness” levels were similar to other times of the day.

“We thought the responses would be greater at night because we tend to overconsume later in the day,” said study coauthor Dr. Lance Davidson, a professor of exercise sciences. “But just to know that the brain responds differently at different times of day could have implications for eating.”

Nevertheless, researchers noted that the study is preliminary and additional work is needed to verify and better understand the findings. The next research steps would be to determine the extent that these neural responses translate into eating behavior and the implications for weight management.

Speaking about further research, Brother Masterson told the Church News, “Since the response that drives you to eat is lower, there must be some other reason for eating so much. If you had the same lower response to eating (since both visual and gustatory are located in the reward pathways), you might have to eat a greater quantity of food to receive the same satisfaction from it. Again, this is our speculation and where future studies should go to understand more.”

Brother Masterson, who is heading to Penn State University to work on his PhD in the fall, said the study has helped him pay better attention to how food makes him feel in the morning and the evening.

“I think that the gospel is essentially a guideline to positive behaviors,” he said. “Included in our scriptural canon are words on healthy eating and exercise (the Word of Wisdom). Part of changing behaviors is understanding and being aware of things that might influence us. This does not provide an excuse for our behavior but rather a starting point to understanding our behavior and starting us on the path to changing for the better.”

In order to understand the scientific aspects of late-night snacking, BYU researchers used functional MRI to monitor the brain to measure how it responded to high- and low-calorie food images at different times of the day. Photo by Jaren Wilkey, BYU.

In order to understand the scientific aspects of late-night snacking, BYU researchers used functional MRI to monitor the brain to measure how it responded to high- and low-calorie food images at different times of the day. Photo by Jaren Wilkey, BYU.