So I looked into whether eating chocolate actually relieves stress, and turns out this one is mostly true, at least for dark chocolate. There's a bunch of real science behind it, not just people saying it because it feels true. One study I found, called "Dark Chocolate Intake Buffers Stress Reactivity in Humans," was published in the Journal of the American College of Cardiology. Basically, they found that when people ate dark chocolate with a lot of flavonoids in it (that's an antioxidant found in cocoa), their stress hormones didn't spike as much when something stressful happened. So it kind of acts like a cushion against stress.
Then there's an older one from 2009 in the Journal of Proteome Research, called "Metabolic Effects of Dark Chocolate Consumption on Energy, Gut Microbiota, and Stress-Related Metabolism in Free-Living Subjects." In this one, people ate dark chocolate every single day for two weeks, and it actually lowered their cortisol (that's the main stress hormone), especially for people who were more anxious to begin with. There's also a newer study from 2019 called "Effect of Polyphenol-Rich Dark Chocolate on Salivary Cortisol and Mood in Adults,".This one tested cortisol levels in people's spit after eating dark chocolate loaded with polyphenols, and it backs up what the older studies already found.
What I thought was actually the most useful one is a 2014 study called "Effects of chocolate intake on Perceived Stress; a Controlled Clinical Study," .This is the one that compared dark, milk, and white chocolate against each other in medical students, using an actual stress survey, so it's not just guessing which kind of chocolate matters. And then to see how this got reported to regular people, I checked out a Live Science article that like basically just explained the study in normal words, saying people who were already stressed out had lower stress hormones after eating chocolate daily for two weeks.
So overall, yeah, chocolate relieving stress is pretty legit, but only really for dark chocolate, and only shown so far in short two-week studies. Milk and white chocolate don't seem to do as much. Also, some of the "feeling less stressed" part could just be because eating something you like feels nice in the moment, not necessarily some special chemical thing happening in your brain. So I'd say the claim is mostly true, but it's not the full picture it works best with dark chocolate, and nobody's proven it fixes long-term stress.