Blame your 'unsatisfying' late night cravings on your brain

When you feel like raiding your fridge in the middle of the night, and you still don't feel full after munching on some goodies, it's all you brain's doing, claims a new study.

Researchers at BYU have shed new light on why you, your friends, neighbors and most everyone you know tend to snack at night: some areas of the brain don't get the same "food high" in the evening.

In a newly published study, exercise sciences professors and a neuroscientist at BYU used MRI to measure how people's 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.

Lead author Travis Masterson said that people tend to over-consume 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 people eat more to try to get satisfied.

The studyalso 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.

The participants viewed 360 images during two separate sessions held one week apart-one during morning hours and one during evening hours.

Subjects looked at images of both low-calorie foods (vegetables, fruits, fish, grains) and high-calorie foods (candy, baked goods, ice cream, 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.

Nevertheless, researchers noted that the study is preliminary and additional work is needed to verify and better understand the findings.

The study is published in academic journal Brain Imaging and Behavior.