It's been a long day. You worked really hard. You deserve chocolate, right? Sure, but it might not be all that wonderful.

A new study published in the American Psychological Association's Journal of Experimental Psychology: Animal Learning and Cognition suggests that although stress makes us crave rewards and motivates us to obtain them, the reward doesn't actually give us that feeling of intense pleasure we'd anticipated.

For the study, conducted at the University of Geneva in Switzerland, researchers recruited 36 university students who described themselves as chocolate lovers and split them into a stress group and a non-stress group. To induce stress, members of the first group had to put one hand in ice water while being observed and videotaped. Members of the non-stress group put their hand in lukewarm water.

Participants from both groups then had to press hand grips for the chance to smell chocolate, and researchers measured the amount of effort they put into it. Those in the stress group worked three times harder squeezing the grip, suggesting they really wanted that reward. But they reported enjoying the aroma no more than those in the non-stress group.

Although participants were only working to smell the chocolate, the results say something about the disconnect between the strength of a stressed person's cravings and the reward in giving in to those cravings.

So why do we want certain foods when we're stressed out? According to a Harvard Mental Health letter, it all has to do with cortisol, a hormone released when we're under stress.

"[C]ortisol increases appetite and may also ramp up motivation in general, including the motivation to eat," the letter reads. "Once a stressful episode is over, cortisol levels should fall, but if the stress doesn't go away -- or if a person's stress response gets stuck in the 'on' position -- cortisol may stay elevated."

If any of this sounds familiar to you and stress-eating is not in your 2015 plans, try implementing mindful eating tips like eating more slowly, paying attention to flavor and silencing distractions like TVs and smartphones.

h/t Science Of Us