A high fat diet leads to overeating because of faulty brain signaling, reveals a new study. In the study, researchers studied one particular signaling pathway in the brain-insulin signaling and the way it works in specific brain cell circuits.
Rapamycin complex 2 (mTORC2) is a group of proteins involved in insulin signaling in the brain. The researchers wanted to find out how insulin signaling and mTORC2 affect how rewarding high fat foods are. They genetically altered brain cells in mice by taking out a part of mTORC2 and found that the mice without a functioning mTORC2 ate high-fat food excessively.
However, when provided only with low-fat food they did not overeat. They also found that the mice whose mTORC2 does not function also had less dopamine in specific regions of the brain which is associated with obesity in humans and animals, and also in escalating substance abuse.
Author Aurelio Galli said that their findings revealed a system that was designed to control eating of rewarding foods that were high in fat and possibly sugar, adding that this system could be hijacked by the very foods that it was designed to control.
He said that eating a high-fat or high-carbohydrate diet felt rewarding, but also appeared to cause changes in the brain areas that were involved in controlling eating, by causing for example insulin resistance.
Galli concluded that their study showed that when specific signaling in these areas of the brain was disrupted, it led to a vicious cycle of increasing, escalating high-fat diet intake which likely further cemented changes in these brain areas. The study is published in the Journal Heliyon