After two weeks...your gut feelings start to change.
People who call themselves “high-anxiety" types experienced a dramatic shift at this point, found a study published in the Journal of Proteome Research. Before they started eating dark chocolate (about 1.5 ounces) daily, their urine and blood samples showed high levels of stress hormones. After two weeks on the regimen, those hormones dropped significantly. The scientists also noted changes in gut-bacteria metabolism, which suggests that microbes in the colon got better at processing—and maximizing the benefits of—flavanol and other healthy polyphenols. Flavanol is also a known prebiotic; it supports the “good guy" bacteria like Lactobacillus that you'd get if you ate that other “soothe-food": yogurt.)