Why Some Women Can't Stop Eating
Researchers have found an answer as to why severely obese women can’t stop eating, even when they aren’t hungry. According to Dr. Nancy Puzziferri, senior author of a new study from UT Southwestern Medical Center, their findings “may explain why some people with severe obesity report an underlying drive to eat continually despite not feeling hungry.”
Many people are familiar with the feeling of not being able to eat just one—one potato chip, one morsel of chocolate, one bite of pizza. Yet for most individuals, that feeling doesn’t translate into a drive to continue eating even after they are full.
What the new study found
The multidisciplinary team compared the brain activity (using magnetic resonance imaging scans) and attitudes of 15 severely obese women and 15 lean women (body weight index greater than 35 and less than 25, respectively). The MRI scans were performed before and after the women consumed a meal, which they ate after fasting nine hours.
Here’s what the researchers found:
- The MRI scans showed significantly increased activity in areas of the brain associated with sensory perception, motivation, and rewards (neocortex, limbic cortex, and midbrain, respectively) in both groups of women when they were hungry.
- After all of the women ate, they were shown pictures of food while undergoing MRI. Brain activity declined in the lean women but continued in the obese women, indicating they were responding to food like they were when they were fasting. According to Puzziferri, “It seems they [the obese women] have an instinctive drive to keep eating.”
- Activity in the midbrain (a potent reward center) remained active in the obese women after they completed their meal, even though they reported the same level of satiation as did the lean women
What does the study mean?
Puzziferri noted that it appears “it’s just not a level playing field” when it comes to trying to maintain a healthy weight. While lean women will stop eating when they are full or perhaps take just a bite or two of something they crave, severely obese women seen to possess a drive to keep eating.
What can experts and obese individuals do to overcome this drive? Although the authors of this study did not answer that question, two approaches could include cognitive behavioral training and medications designed to suppress the brain activity that supports the underlying drive to continue eating.
Puzziferri N et al. Brain imaging demonstrates a reduced neural impact of eating in obesity. Obesity (Silver Spring) 2016 Apr; 24(4): 829-36
UT Southwest Medical Center
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