This may not be news to you, but it is good to know that there's some science behind the theory that chocolate makes us happy: eating dark chocolate (1.4 ounces of it, to be exact) every day for two weeks reduced stress hormones, including cortisol, in people who were highly stressed. Experts believe it could be thanks to the antioxidants in chocolate. When you do indulge, be sure to account for the 235 calories that 1.4 ounces of chocolate delivers-or you may be stressed to see extra pounds creeping on.

Despite persistent myths to the contrary, carbs don't make you fat and they can boost your mood. In a new study in the Archives of Internal Medicine, people who for a year followed a very-low-carbohydrate diet-which allowed only 20 to 40 grams of carbs daily, about the amount in just 1/2 cup of rice plus one piece of bread-experienced more depression, anxiety and anger than those assigned to a low-fat, high-carb diet that focused on low-fat dairy, whole grains, fruit and beans. Researchers suspect that carbs promote the production of serotonin, a feel-good brain chemical. Also, the challenge of following such a restrictive low-carb diet for a full year may have negatively impacted mood.

Another reason to eat healthy, whole foods! In a recent study of close to 3,500 men and women published in the British Journal of Psychiatry, those who reported eating a diet rich in whole foods in the previous year were less likely to report feeling depressed than those who ate lots of desserts, fried foods, processed meats, refined grains and high-fat dairy products. Previous studies have shown that antioxidants in fruits and vegetables and omega-3 fatty acids in fish are associated with lower risk of depression. Folate, a B vitamin found in beans, citrus and dark green vegetables like spinach, affects neurotransmitters that impact mood. It's possible that the protectiveness of the whole-food diet comes from a cumulative effect of these nutrients.

Eating oily, fatty fish (salmon, tuna, sardines, rainbow trout) and mussels will give you omega-3s-a key mood-boosting nutrient and one our bodies don't produce. Omega-3s alter brain chemicals linked with mood-specifically dopamine and serotonin. 

In one study, from Iran's Roozbeh Psychiatric Hospital at Tehran University of Medical Sciences, 50 women with PMS were given two (15 mg) saffron capsules or placebo capsules daily over two menstrual cycles, keeping track of their symptoms in diaries. By the end of the study, over three-quarters of the women who had taken the equivalent of a micropinch of saffron reported that their PMS symptoms (such as mood swings and depression) declined by at leasthalf, compared with only 8 percent of women in the placebo group. In earlier studies, saffron had antidepressant effects comparable to the antidepressants fluoxetine (Prozac) and imipramine (Tofranil). Researchers believe that the spice works by "the same mechanism as Prozac," helping to make the feel-good neurotransmitter serotonin more available to the brain.

When you're stressed, the scent of coconut may blunt your natural "fight or flight" response, slowing your heart rate. People who breathed in coconut fragrance in a small pilot study at Columbia University saw their blood pressure recover more quickly after a challenging task. The researchers speculate that inhaling a pleasant scent enhances alertness while soothing our response to stress.

Fuzzy brain? Drinking caffeinated black, green or oolong tea may elicit a more alert state of mind, says a study in The Journal of Nutrition. Researchers think theanine-an amino acid present in these tea varieties-may work synergistically with caffeine to improve attention and focus. To reap the benefits, the study's results suggest drinking 5 to 6 (8-ounce) cups of tea daily.