According to research published in Human Brain Mapping, a single bout of exercise may increase the reactivity of the brain to food cues in areas of the brain responsible for attention, memory, and anticipation of reward.
Researchers from Loughborough University, the University of Bristol, the University of Nottingham, the University of Leicester, and Waseda University in Japan investigated the effect of running on the blood flow of the brain and how this influenced the brain’s activity in relation to appetite. They discovered that changes in the way participants responded to visual food cues occurred independently of the overall changes to blood flow in the brain.
The amount of food we consume is influenced by certain systems in the brain that are responsive to changes in our bodies and the food environment we are in. Previous studies have shown that brief bouts of exercise, such as running, can temporarily suppress appetite. However, the effects of exercise on our likelihood to eat are not yet fully understood.
Food cue reactivity is defined as how our bodies respond to food. It includes the physical and psychological response we have to the sight or smell of food. Food cue reactivity can influence both our appetite and how much we end up eating.
The study team set out to investigate whether exercise-induced blood flow changes in the brain could affect how people react to food. Functional magnetic resonance imaging (fMRI) can capture these changes, allowing researchers to evaluate brain activities by detecting small changes in blood flow.
For the study, twenty-three men underwent fMRI scans both before and after a 60-minute session of running or rest. During the scan, they were shown three different types of images, including low-energy dense foods, such as fruits and vegetables, high-energy dense foods, such as chocolate, as well as non-food items like furniture.
The researchers discovered that the single bout of exercise suppressed feelings of hunger in participants, but increased reactivity of various parts of their brains to food cues. Using a different type of fMRI, the study team also detected changes in blood flow in the brain after exercise, even though these did not appear to have an effect on the food cue reactivity signals.
Dr. Alice Thackray, a Senior Research Associate in Exercise Metabolism at Loughborough’s School of Sport, Exercise, and Health Sciences, led the study and said, “Our findings confirm individuals feel less hungry during and immediately after an exercise session and provide some insights into the short-term influence of exercise on brain appetite responses.”
She added: “Although additional research is needed to determine the implications of these findings, we know the brain plays an important role in the control of appetite and food intake. This study is part of an exciting collaboration that we plan to develop further as we continue to explore how exercise and appetite interact, including the influence on central (brain) responses.”
David Stensel, Professor of Exercise Metabolism in SSEHS, added, “The role of exercise in modifying appetite and assisting with weight control remains a hotly debated topic. This research demonstrates that how our brains respond to food cues can be altered by exercise.”
He further stated that this study provides a foundation for further work to refine characterizations of appetite responses to exercise comprehensively. This will give us a better understanding of the role of exercise in preventing and managing unhealthy weight gain.
Dr. Elanor Hinton from Bristol University said, “This research began as a small pilot collaboration between two NIHR BRCs in Loughborough and Bristol. We are delighted that our initial plans have grown to produce this publication in Human Brain Mapping, in which we have shared our respective expertise. A further publication is now pending from this fruitful collaboration, demonstrating the value of collaboration across our research groups.”
In conclusion, this study provides valuable insights into how exercise impacts the brain’s reactivity to food cues. It may help us better understand the role of exercise in the regulation of appetite and weight management. Nonetheless, further research is required to comprehend the far-reaching implications of the findings.
