Fasting to lose weight could change how your brain works, study finds

Laura Hampson
Updated ·3 min read
fasting plate
Scientists believe fasting could impact the area of the brain that affects obesity. (Getty Images)

Fasting, particularly intermittent fasting, has become a popular diet method in recent years – but now new research has found that it could actually alter the brain.

The small-scale study came from researchers in China who analysed 25 volunteers over a period of two months.

During this time, the volunteers took part in an intermittent fasting programme, which saw the participants lose 16.8lbs, or 7.6kg, each on average.

Along with the weight loss, scientists also noticed that there were signs of shifts in the activity of their brain that is linked to obesity, as well as in the makeup of their gut bacteria.

"The observed changes in the gut microbiome and in the activity in addiction-related brain regions during and after weight loss are highly dynamic and coupled over time," study author Qiang Zeng from the Second Medical Center and National Clinical Research Center for Geriatric Diseases in China, said.

The scientists are still unclear what exactly causes these changes in the brain and the gut, or whether the brain is influencing the gut first or vice versa.

Woman hands holding intestine shape, healthy bowel digestion, leaky gut, probiotic and prebiotic for gut health, colon, gastric, stomach cancer concept
Scientists are till trying to understand the relationship between the brain and the gut. (Getty Images)

However, the areas where the scientists saw the change in brain activity during the fasting were in the regions that control appetite and addiction.

After analysing stool samples, the researchers also saw gut microbiome changes that are linked to brain regions that can control willpower which helps in terms of food intake.

"The gut microbiome is thought to communicate with the brain in a complex, two-directional way," researcher Xiaoning Wang from the State Clinic Center for Geriatrics in China, said.

"The microbiome produces neurotransmitters and neurotoxins which access the brain through nerves and the blood circulation. In return the brain controls eating behavior, while nutrients from our diet change the composition of the gut microbiome."

The researchers add that they now need to understand how the gut microbiome and brain communicates with obese people, particularly obese people who are trying to lose weight.

In doing this, they hope to pinpoint the specific brain regions and gut microbiome that can help with weight management and weight loss.

Several previous studies have looked into the benefits and pitfalls of intermittent fasting. One study from earlier this year found that it can raise cardiovascular risk, while another claimed it may shorten someone’s lifespan.

Other studies have found that intermittent fasting can be beneficial for blood pressure, resting heart rate, reducing the risk of type 2 diabetes, and helping with weight loss.

Fasting: Read more