Is Junk Food “Sensitivity” to Blame?

junk foodIt is estimated that over 34 % of adults over the age of 20 are currently obese and due in part to a lack of propensity towards healthy food, diets and exercise regimes, this number is continuously growing.  Obesity is a serious health issue and it vastly increases a person’s likelihood for developing cardiovascular disorders such as heart disease and high blood pressure.  However, the risk of obesity does not end there; obesity also increases your likelihood for developing diabetes, osteoarthritis, sleep apnea, varicose veins, abdominal hernia, gout, respiratory problems, liver malfunction and gall bladder disease.

Obesity is a complex disorder; it is caused by more than just excessive caloric intake and inactivity. According to Mayo Clinic, certain genes, inactivity, quitting smoking, sleep deprivation, pregnancy, antidepressant medications, low income and consuming a diet void of healthy foods can all increase your risk of obesity.  In addition, a recent study published by Cell Press in the journal Trends in Endocrinology and Metabolism has found that a sensitivity to junk food advertising, in combination with its easy accessibility, can also vastly increase your risk of obesity.


The study was conducted by scientists at the Montreal Neurological Institute, at McGill University and authored by Dr. Alain Dagher. The researchers involved in this study used functional neuroimaging, in order to investigate the neural response to junk food exposure, in both obese and non-obese individuals.  Functional neuroimaging is a commonly used technology that allows for a non-invasive diagramming of brain activity and helps scientists to better understand the neural control of eating in humans.  “There has been great interest in looking at the brain for the source of vulnerability to overeating in a world of cheap, abundant, high-calorie food. As a result of this research, differences (in brain activity) between lean and obese individuals are starting to emerge,” states Dr. Alain Dagher.

Through the use of neuroimaging, the scientists were able to identify a brain network that is responsible for appetite control. More specifically, they discovered that this network creates signals that motivate a person to eat, and they found that reward networks play a chief role in determining ones food intake choices.  According to this study, advertising for high-calorie junk foods and exposure to them in everyday life, whether at the supermarket, at a party, or in your own kitchen, turns on anticipatory signals in your brain. Obese individuals are more sensitive to junk food exposure, and when they are exposed to sweet or fatty food cues, they experience a more vehement brain activation, which consequently increases their motivation to consume junk food.  In addition, obese individuals tend to produce more of the neurotransmitter dopamine in response to junk food cues. This is problematic because dopamine motivates a person to indulge in the behavior, or in this case, to consume the food, that activates it.

“The emerging imaging literature supports the view that although there is not a single pathway leading to obesity, it is a neurobehavioral problem: a disease that results from a vulnerable brain in an unhealthy environment,” explains Dr. Dagher.  This research proves that obesity is not merely a result of unhealthy diets and exercise, and that it is indeed much more complex. Hopefully, this new understanding of obesity will help scientists and perhaps even politicians (via laws against junk food advertising), to develop effective methods to combat the disease and eradicate the global obesity epidemic.


Related Reading: Too much of a good thing? Don’t overeat these health foods