It's an adage so widely known, it's nearly a joke: When premenstrual syndrome (PMS) strikes, women reach for chocolate. But they may think it's just a little pick-me-up without any real scientific benefit. Even 10 or 15 years ago, women's magazines advised that sweets would actually make premenstrual women's moods worse.
However, studies show chocolate really does ease PMS symptoms, such as anxiety, anger, mental fogginess or temporary sadness. Researchers even mapped out a timeline to illustrate chocolate's effects. The texture and taste of chocolate get the ball rolling, but even as the immediacy of this pleasure fades, another positive effect takes hold: chocolate suppresses feelings of fatigue and irritation, sometimes for several hours. Chocolate also contains trace minerals, including magnesium, which can become depleted during menstruation [source: Fit Day].
How does chocolate work its wonders? Researchers propose it has to do with chocolate's ability to set off mood-altering chemicals, like serotonin, in the brain. Serotonin is often low in the week before a period. A study at MIT found chocolate and carbohydrates were a particularly powerful combination. When the study's premenstrual subjects ate chocolate brownies, for example, the brain's serotonin levels soared. Women who aren't chocolate fans can still lighten the mood by snacking on carbs, such as oatmeal or yogurt, to downplay the body's reaction to PMS [source: Wurtman].