Eating too many sugar cookies and white bread products this holiday season could be the reason you’re in a funk. A new study published in the American Journal of Clinical Nutrition of 70,000 postmenopausal women found those who consumed carbs with a high glycemic index rating (such as white bread, white rice, or sugary sodas) were more likely to suffer from fatigue, moodiness, and depression.

“High levels of refined carbs and sugars in your diet can increase inflammation in the body, as well as decrease the number of essential nutrients you’re taking in,” says Drew Ramsey, M.D., an assistant clinical professor of psychiatry at Columbia University in New York and the author of The Happiness Diet. On the other hand, women who follow a diet rich in fiber, whole grains, vegetables, and fruits have a decreased risk of depression, according to the study.

“The optimal diet for brain health is high in phytonutrients, iron, vitamin B12, and zinc,” says Ramsey. On the list of the best foods for happiness: seafood (wild salmon, mussels, clams, anchovies, oysters); nuts and seeds; leafy greens; beans (especially red beans and lentils); and our personal favorite, high-quality dark chocolate.