Obesity reduces brain’s power to sense nutrients and release dopamine

Obesity may change the way your brain works

Scientists primarily focus on the physical ailments caused by obesity, but little is known about its effect on brain functions. The study authors suggest that the eating behavior of an obese person is influenced by the changes obesity brings to their brain.

They also experimented to prove this point. Their study involved two groups; the first group had 30 people with average healthy body weights, and the second included 30 people with obesity. 

They introduced some nutrients into the participants' stomach and then examined their brains using MRI and SPECT (single-photon emission computerized tomography). 

While MRI allowed the researchers to monitor the brain’s response to the nutrients, SPECT enabled them to keep an eye on the release of dopamine hormone that indicates the motivation and pleasure a person derives from food.   

The researchers noticed that the brains of healthy bodyweight people released more dopamine and responded more actively to the infused nutrients than people with obesity. 

Serlie explained, “These findings suggest that sensing of nutrients in the stomach and gut and/or of nutritional signals is reduced in obesity, and this might have profound consequences for food intake.” 

Moreover, when the researchers made the obese participants lose 10 percent of their body weight in the following weeks and again scanned their brains. They were surprised that their brain’s capacity to sense nutrients and release dopamine didn’t restore to normal.

This also indicates that the changes obesity causes in a person's brain are long-lasting, affecting a person's eating behavior for a long time. This may explain why many people with obesity find it difficult to change their diet and regains weight even after losing it once.

The strange connection between food intake and brain activity

Do you know why we sometimes have a craving for a particular food? Well, craving mostly occurs because your brain signals that your body is experiencing a lack of nutrients is stressed or dehydrated, or is running low on blood sugar. 

Usually, when you crave a snack, after eating it, your body’s demand is met, a good amount of dopamine is released, and you feel good. 

However, if you don’t feel good even after consuming the craved food item, your body doesn’t need that in the first place. This is what possibly happens in the case of people with obesity.

They're likely to eat more of the craved item to make themselves feel better since obesity hinders their brain’s ability to fully sense the nutrients and reward them with adequate dopamine release.  

According to the researchers, a person's food intake is affected by a network of various metabolic and neuronal pathways. “This network triggers sensations of hunger and satiation and regulates food intake as well as the motivation to look for food,” notes the researcher.

Until now, scientists have been able to study such networks in animals only. However, their connection with obesity might also make it easy for them to study in humans.  

Hopefully, the current research work will help scientists better understand how obesity affects these pathways and play an essential role in shaping a person’s eating habits in the long term. 

The study is published in the journal Nature Metabolism.