New study reveals that fluctuating—not just intense—brain signals play a hidden role in overeating

A groundbreaking study published in Translational Psychiatry examined the complex relationship between fluctuating brain signals and overeating tendencies. Researchers from the University of Tübingen in Germany investigated whether inconsistency in the brain's reward processing may contribute to overweight and binge eating disorder.

The study focused on specific brain regions, the nucleus accumbens and the dorsolateral prefrontal cortex, known for their roles in reward anticipation, pleasure, motivation, and cognitive control. A diverse group of 79 women, including those with binge eating disorder, subsyndromal binge eating disorder, and controls, participated in the research.

Participants underwent a grip force effort allocation task where they earned monetary rewards or snack foods by squeezing a handgrip device. The task's difficulty ranged from explicit to uncertain, with participants rating their desire for the reward and effort exerted after each round. Binge eating disorder participants exhibited higher variability in their desire ratings, especially during uncertain trials, while their physical effort remained consistent.

This suggests a disconnect between fluctuating internal desire and steadier external behavior. In a second phase, participants returned after fasting and underwent functional MRI scans while completing the same handgrip task. Greater fluctuations in the nucleus accumbens correlated with higher body mass index and disinhibited eating tendencies.

These findings indicate that inconsistent brain signals may play a significant role in eating behaviors, particularly in binge eating disorder, challenging previous assumptions that focused solely on the average strength of brain signals during food exposure.