There are times when for no particular reason, you're feeling lower than a snake's belly: a little on the weepy side, kind of listless, thinking a big chunk of chocolate would lift you right up. I've been through these. Sometimes, without much effort--the weather changes, the check actually is in the mail--the mood passes, and all's right with the world. But if you're stuck in Dumpsville or Crapsville, try the 30-minute miracle meal: a low-fat, low-protein, high-carbohydrate snack: Think toasted English muffin with a dollop of blueberry jam seeping into those nooks and crannies. Yummy!

When high-carbohydrate food isn't bogged down by the presence of protein or fat, they allow an amino acid called tryptophan to flood your brain, where it morphs into serotonin, a neurotransmitter that boosts mood and curbs food cravings (such as your chocolate yearnings). As a bonus, it helps you tolerate pain and can even help you sleep like a baby. And all that happens in just half an hour.

You could also have a piece of whole wheat bread with some honey or a bowl of air-popped popcorn, suggests Elizabeth Somer, RD, author of Food & Mood. But skip the protein foods such as cheese, chicken, or turkey. "They suppress serotonin," she says, "because all the other amino acids in them compete with tryptophan, so it can't get into your brain." If you really need chocolate, avoid the usually creamy, fatty kind (sorry), and drizzle fat-free chocolate syrup over cut-up fruit or an English muffin for a do-it-yourself pain au chocolat. Boost thy mood!