A study by a group of international researchers reveals the perception of hunger, or a food craving, activates a different brain network in obese and normal weight patients.
Scientists believe this indicates the tendency to want food may be “hard-wired” into the brain of overweight patients, becoming a functional brain biomarker.
Obesity is one of the most difficult problems facing modern society. Treating obesity is a health priority, but most efforts (aside from bariatric surgery) have met with little success.
Experts believe the low success rate in care for obese patients is at least in part, a function of limited scientific knowledge of the mechanisms associated with the desire to eat.
Emerging studies are now beginning to suggest that the brain mechanisms underlying obesity may be similar to those in substance addiction, and that treatment methodologies may be approached in the same way as other substance addictions, such as alcohol or drug addiction.
To test this hypothesis, a group of researchers from the University of Granada, Spain, and Monash University in Australia, looked for the functional connectivity differences in brain reward systems of normal-weight and obese individuals.
The researchers gave buffet-style food to 39 obese and 42 normal-weight individuals. Later, they were put into functional MRI brain scanners and shown photographs of the food to stimulate food craving.
The fMRI scans showed that food craving was associated with different brain connectivity, depending on whether the subject was normal-weight or overweight.
They found that in obese individuals, the stimulus from food craving was associated with a greater connectivity between the dorsal caudate and the somatosensory cortex, implicated in reward-based habits and the coding of the energetic value of foods, respectively. However, with normal weight individuals, food craving was associated with a greater connectivity between different parts of the brain.
The researchers then measured Body Mass Index (BMI) three months afterwards and found that 11 percent of the weight gain in the obese individuals could be predicted by the presence of the increased connectivity between the dorsal caudate and the somatosensory cortex areas of the brain.
According to lead researcher Dr. Oren Contreras-Rodríguez, this finding supports the idea that the reward processing following food stimuli in obesity is associated with neural changes similar to those found in substance addiction. However, the discovery still needs to be viewed as an association between food craving behavior and brain changes, rather than one necessarily causing the other.
Nevertheless, Contreras-Rodríguez said the findings do provide potential brain biomarkers which can be used to help manage obesity. For instance, he believes pharmacotherapies and brain stimulation techniques can be developed that may help to control food intake in clinical situations.