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Your Mood

When you're in need a pick-me-up, there's a biological reason why you crave chocolate and candy. When sugar hits your tongue it activates a dopamine flood in your brain that pings regions associated with pleasure and reward, says neuroscientist Nicole Avena, PhD, author of Why Diets Fail. The brain then establishes a link between sugar and feeling good, so you seek it out automatically when sad or stressed. Problem is, the end result may also leave you feeling down in the dumps and constantly irritable. "Dopamine also influences other hormones, like cortisol (the stress hormone). And cortisol is affected by blood-sugar levels, so if they're constantly going up and down all day [thanks to added sugar], so will your stress hormones," Avena says.