weight fluctuations

A new study was done to see if pleasurable (palatable) foods increase weight fluctuations as a measure to predict future weight gain. It was determined that palatable foods do increase weight variability when the reward system in the brain is active, contrasted by a decreased variability when an individual is more self-aware.


The prevalence of obesity is growing at an alarming rate with a minimal number of treatment options that actually produce long-term weight loss. Studies have therefore been done to try and determine factors that can predict weight variability to design better weight-control interventions. However, just measuring the net weight change is not enough because an individual’s body weight fluctuates, so the variability in body weight could change independently of the actual net weight change. In fact, the amount of variability in an individual’s body weight might be able to predict their ability to regulate their body weight in the future. This is an important process to understand when attempting to find new ways to better treat those with obesity. Knowing that pleasurable, or palatable, foods increase the response of the brain’s reward system, which in turn, increases body weight, a new study conducted by Winter et al. attempted to see if the increased response of this reward system would also affect future weight variability.

Using 162 healthy-weight adolescences (14-18 years), the subjects were assessed once a year for 3 years, ending the study with 127 subjects. Prior to each assessment, each subject had their BMI calculated. Using an MRI scan, the neural response during the time of a cue indicating an impending milkshake, and then again during milkshake reception, was investigated. Using these results, weight variability was calculated based on each of the four BMI’s measured (baseline, year 1, year 2, year 3) and then were compared to the brain activity of the MRI scans. These scans looked at specific activity in the medial prefrontal cortex, cingulate cortex, and insula, which are all associated with the regions of the brain that control reward and emotion. Activity was also looked at in the precuneus, which is the region that controls self-consciousness.

It was found when there was more activation of the brain’s reward centers, there was a higher fluctuation in body weight, which could predict an increase in future weight. It was also found that there was an inverse correlation with the precuneus; when this area was more active, there was less body weight variability.  Therefore, it was determined that a strong reward response to palatable high-calorie foods is linked to an increase in weight variability, which might positively correlate with an individual’s ability to control one’s weight in the future. This study did not examine the net weight change of the individuals, and in future studies this may be an important factor to look at, as well as weight variability, when attempting to design weight-preventative programs for teens.


Written By: Unaisa Bhayat, M. D. Candidate

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