Researchers have discovered that some areas of the brain don’t get the same food high in the evening as during the day, explaining at least partly why night snacks work so well.
Exercise sciences experts and a neuroscientist at Brigham Young University used MRI to measure how brains respond to high and low calorie food images at different times of the day.
The results showed that images of food, especially high-calorie food, can generate spikes in brain activity but those neural responses are lower in the evening.
"You might over-consume at night because food is not as rewarding, at least visually at that time of day," said researcher Travis Masterson. "It may not be as satisfying to eat at night so you eat more to try to get satisfied."
The study, in the journal Brain Imaging and Behaviour, 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 over-consume later in the day," said 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."
The researchers noted the study is preliminary and additional work is needed to verify and better understand the findings.
The next research would be to determine the extent that these neural responses translate into eating behaviour and the implications for weight management.
Masterson said the study has helped him pay better attention to how food makes him feel both in the morning and the evening.
And his night eating habits?
"I tell myself, this isn’t probably as satisfying as it should be,” he said. “It helps me avoid snacking too much at night."