Fascinating scans show that obesity affects a person's brain structure.
A study that collected MRI scans of thousands of people of varying sizes found that people carrying dangerous levels of weight have "smaller volumes of important brain structures".
Less gray matter indicates a loss of nerve cells, while changes in the white matter may affect the transmission of electrical signals in the vital organ.
Because the gray matter plays a role in our reward center, these changes can make it difficult for overweight people to control their weight, the researchers claim.
Obesity is believed to cause inflammation that damages the brain tissue. This is unclear.
An MRI scan shows the crown of two 65-year-old women's heads. The left participant had a body fat percentage of 13 percent, while the right part was 49 percent. Researchers claim that the right MRI shows "lower levels of subcortical gray matter structures"
The research was carried out by the Leiden University Medical Center in the Netherlands and by the radiologist Dr. med. Headed by Ilona Dekkers.
"We found that higher levels of fat in the body are associated with smaller volumes of important brain structures, including the gray matter structures that are at the center of the brain," Dr. Dekkers.
"Interestingly, we found that these associations are different for men and women, suggesting that gender is an important driver of the relationship between fat content and the size of certain brain structures."
HOW DOES OBESITY WORK ON THE BRAIN?
The influence of obesity on the brain is barely known and a growing field of research.
A study by the University of Alabama suggests that weight gain affects our cognitive function even in people without dementia.
Brain scans of morbidly obese patients show that older people carrying dangerous levels of weight show higher brain cell depletion.
Whether this is also the case in younger patients is unclear.
Obesity is also associated with a reduced attention span as well as a slower engine speed and information processing.
Older people are increasingly affected, which can be associated with the age of cognitive functions anyway.
Reduced cognitive functions can impair the ability of an obese person to lose weight.
Bad memory and poor functioning are also associated with the "slipping" of patients after bariatric surgery.
Source: Psychology today
Obesity is a global problem. 26 percent of adults had a dangerous weight in the UK in 2016, according to NHS statistics.
According to the Centers for Disease Control and Prevention in the United States, between 2015 and 2016, 39.8 percent of adults were overweight.
To find out how obesity affects the brain, researchers analyzed the MRI scans of 12,087 participants in the UK biobank study.
Since its inception in 2006, Biobank has collected the genetic information of half a million people and aims to discover how DNA and lifestyle factors affect our disease risk.
The scans were done with state-of-the-art technology that differentiates between gray and white matter.
"MRI has proven to be an irreplaceable tool for understanding the link between neuroanatomical differences in the brain and behavior," Dr. Dekkers.
In simple terms, the gray matter contains the mass of our nerve cells, while the white matter consists of long filaments that transmit electrical signals between the neurons.
The results published in the journal Radiology showed that the weight of the participants led to clear differences in the composition of their brain.
"Our study shows that very large data collection of MRI data can lead to better understanding of which brain structures are involved in all kinds of health outcomes, such as obesity," Dr. Dekkers.
These results were also sexual. The men with a higher body fat percentage had a lower volume of gray matter. They also had impaired structures related to rewards circuitry and movement.
A reward circuit refers to a group of structures activated by a reinforcing stimulus, such as addictive.
MRI scan again shows the reduced gray substance in the larger participant (right)
The change in brain structure between the slender (left) and the heavier (right) woman is evident from a different angle. Less gray matter indicates fewer neurons impacting our reward center.
The results further showed that the larger female participants had reduced activity in their globus pallidus, a structure that regulates voluntary movement.
In both men and women, a higher body fat percentage increased the likelihood of microscopic changes in the white matter of their brain.
However, the study examined only the body fat percentage and did not differentiate between different types of fat, the researchers emphasize.
Of particular interest is the visceral white fat that surrounds our internal abdominal organs, which increases our risk of heart disease and type 2 diabetes.
The author of the study, dr. Hildo Lamb, professor of radiology, added: "For future research it would be of great interest if differences in body fat distribution are related to differences in the morphological structure of the brain.
"Visceral fat is a known risk factor for metabolic diseases and is associated with systemic low-grade inflammation."