Obesity linked with reduced brain plasticity in new study

Severely overweight people are less likely to be able to re-wire their brains and find new neural pathways, which could have significant implications for people recovering from a stroke or brain injury, according to a new study by the University of South Australia published in the journal Brain Sciences.

Using a series of experiments involving transcranial magnetic stimulation, the researchers tested 15 obese people aged between 18 and 60, comparing them with 15 people in a healthy-weight control group.

Repeated pulses of electrical stimulation were applied to the brain to see how strongly it responded. The healthy-weight control group recorded significant neural activity in response to the stimulation, suggesting a normal brain plasticity response. In contrast, the response in the obese group was minimal, suggesting its capacity to change was impaired, according to the study.

Obesity is based on body mass index (BMI), which calculates the ratio between height and weight to determine body fat. An adult who has a BMI between 25 and 29.9 is considered overweight. Anything above that is obese, the researchers said.

The results show that brain plasticity is impaired in obese people, making it less likely that they can learn new tasks or remember things, the researchers said.

"These new findings suggest that losing weight is particularly important for healthy brain ageing,” said Brenton Hordacre, PhD, researcher at the university, in a statement, “or for recovery in people who suffer strokes or brain injuries, where learning is fundamental for recovery."