Why we reach for chocolates during stress?

A study led by the University of Texas Southwestern Medical Centre suggests that ghrelin - the so-called "hunger hormone" - is involved in triggering this response to high stress situations.

"This helps explain certain complex eating behaviours and may be one of the mechanisms by which obesity develops in people exposed to psychosocial stress," said Jeffrey Zigman, assistant professor of internal medicine and psychiatry at the Medical Centre.

"We think these findings are not just abstract and relevant only to mice, but likely are also relevant to humans," added Zigman, who led the study, reports the Journal of Clinical Investigation.

Scientists know that fasting causes ghrelin to be released from the gastrointestinal tract, and that the hormone then plays a role in sending hunger signals to the brain, according to a Texas statement.

Zigman's lab has previously shown that chronic stress also causes elevated ghrelin levels, and that behaviours linked with depression and anxiety are minimized when ghrelin levels rise.

In mice, these stress-induced rises in ghrelin lead to overeating and increased body weight, suggesting a mechanism for the increased prevalence of weight-related issues observed in humans with chronic stress and depression.