Consider this the holy trinity of stress-busting snacks. Not only do oats help stabilize your mood, thanks to their B vitamins, "but berries provide a healthy dose of vitamin C—great for keeping stress at bay—while walnuts are packed with happiness-boosting omega-3s," explains Natasha Uspensky, a holistic health and nutrition counselor. "Quick or slow-cooking stovetop oats (either rolled or steel-cut) are generally healthier than the instant microwaveable kind, but in a pinch, you can heat up instant oats with boiling water," notes Uspensky.