Obesity May Be a Disease of the Brain, Say Researchers

Researchers at Macquarie University in Sydney, Australia have shown that memory inhibition – our ability to 'block out' memories that aren’t functional any more, which relies on a part of the brain called hippocampus – is connected to dietary excess. Therefore, they believe obesity may be a disease of the brain, which involves progressive decay of many cognitive processes that influence eating.

Normally, memories that are related to food should be at the front-line during hunger but then is blocked when a person is full making thoughts of food set aside when we are not very hungry.

Previous studies on animals have shown that a Western style diet, which consists of food high in fat and sugar and low in vegetable, fruit and fiber, damages the hippocampus’ abilities to inhibit memory inhibition. This could suggest that a Western diet makes it more difficult to hamper happy memories triggered by smelling or seeing tasty food. For this reason, it’s hard for someone to resist savory foods even if they are full.

The researchteam led by Tuki Attuquayefio, a PhD student, examined healthy young participants, some of whom consumed a Western diet.

Participants were required to completememory and learning tests that rely on the hippocampus. They also revealed and rated how much they liked and desired tasty snack foods before and after a consuming a filling lunch. Participants who commonly consumed a Western diet took longer to learn something and were worse at remembering things compared to those who consumed a healthierdiet. More importantly, those who ate western diet showed much smaller cutbacks in craving for savory snacks when feeling full compared to feeling hungry.

The crucial finding, say the researchers, is that there is a link between memory performance and ratings of snack food.

"Even though they were full, they still wanted to eat the sweet and fatty junk food," explained Tuki Attuquayefio.

"What was even more interesting was that this effect was strongly related to their performance on the learning and memory task, suggesting that there is a link between the two via the hippocampus."

The researchers believe that based on the animal testing, people who consume a western-style diet may perform poorly on memory and learning tests because of how their hippocampus is impacted by food. They say that inability to hinder memories of food when in a satiated physiological condition could then explain the unrelenting appetite for snacks. For otherwise young, healthy, lean people who routinely eat high-fathigh-sugar diets, compromised function of their hippocampus may make it more difficult to control eating food and make them follow the path towards obesity. Therefore, they say their findings suggest that obesity is a disease of the brain.

The researchers reported their findings at the annual meeting of the Society for the Study of Ingestive Behavior (SSIB), the foremost society for research into all aspects of eating and drinking behavior.