Various researchers and researches lead by Stephanie Fulton from CHUM Research Center and University of Montreal discovered that consumption of large amount of fat can result in impairments in the functioning of mesolimbic dopamine systems, which is a critical pathway controlling motivation.
Fulton further stated that “research shows that independent of weight gain and obesity, high-fat feeding can cause impairments in the functioning of the brain circuitry profoundly implicated in mood disorders, drug addiction, and overeating - several states and pathologies that impinge on motivation and hedonia".
Fulton also stated that, “Another key finding is that the effects of prolonged high-fat feeding to dampen the sensitivity of this brain reward system are specific to saturated fats - palm oil used in this study - but not monounsaturated fat such as the olive oil used in this study”.
These findings and data were obtained by the researchers by analyzing three groups of rats. The very first of the rat group was the control group. This group of rat was given a diet with low fat content and approximately equal amounts of saturated and monounsaturated fatty acids.
The second group of rats was given diet with high amount of monounsaturated fat. Fifty percent of the calories form the diet mentioned above were taken from the fat excreted from olive oil.
The third and the last group of rats was given a diet with high saturated fat content. Just like before fifty percent of calories were extracted from fat but palm oil was used for the process this time instead of olive oil.
The diet with high content of fat was all the same in terms of proteins, fat content and caloric density and sugar. These rats were to eat as much they wanted or as little as they wanted.
After approximately eight weeks, all the rats from all the three groups had comparable body weight and insulin levels, leptin (which is one of the significant metabolic hormones) and relative glycemia.
Simultaneously the rats went through a series of biochemical and behavioral tests which are significantly known to be indicative of the functioning of the dopamine system of the rats.
Cecile Hryhorczuk, the first authority of the research said "We established that the rats on the palm diet had a significantly blunted dopamine function". He further stated that "Our research group and others hypothesise that this leads the brain to try to compensate by heightening reward-seeking behaviour, much like the phenomenon of drug tolerance where one has to increase the drug dose over time to get the same high."So, a person consuming too much saturated fat may then compensate a reduced reward experience by seeking out and consuming more high-fat and high-sugar foods to get the same level of pleasure or reward".
The research is the very first of its own kind to make a statement that irrespective of the changes in the weight, unrestrained or uncontrolled consumption of fats which are saturated can have negative and ill effects on the controls of motivation of the brain.