Now that you’ve eaten your weight (or more) in Halloween candy and partied your costumed heart out all weekend, you’re probably not feeling your absolute best. This could be for a multitude of reasons: You’re hungover, your costume wasn’t quite as original as you thought, or you’re a little sick because you decided to dress as a mermaid in 58-degree weather. But another reason you might not be feeling so hot? Your gut.

Our body has about 2 to 3 pounds of bacteria, and tens of trillions of those microorganisms live right in our stomach. While some germaphobes may be cringing and pulling out their hand sanitizer, these bacteria are actually really important and largely beneficial. Our intestinal “microflora,” as many scientists call them, help our intestines digest food, battle diseases and lose weight, all while powering 60 percent of the body’s immune system. Essentially, these bacteria are our best friends.

Unfortunately, the bacteria in our stomachs aren’t always perfectly balanced. While our body naturally wants us to be the healthiest we can be, what we consume has a huge effect on the microorganisms in our intestines. Taking antibiotics will destroy both the good and the bad bacteria, resulting in decreased bacterial diversity and suppressed healthy bacterial growth for up to sixteen months. Stress — a UC Berkeley student’s best friend — can also repress the immune system, which opens the door for bad bacteria to flourish. Along with overeating sugar, refined carbs, and red meat — foods that specifically feed those bad bacteria — our entire body can be thrown into whack. Worst of all, these less-than-friendly organisms can make us crave unhealthy things even more, creating a vicious cycle.

Luckily for us, there are only two things you need to kick start your progress toward your healthy gut: pre- and probiotics. Probiotics are one type of good bacteria similar to the ones already in your stomach. By eating these, you’ll help diversify your “gut flora” and aid digestion. Then, reinforce your bacteria with prebiotics — plant-fiber compounds that stimulate the growth of good bacteria. With these two to help you out, you’ll feel much better in no time.

Some common probiotics include dairy (yogurt, kefir), kimchi, miso, tempeh, sourdough bread and kombucha.

Some common prebiotics include leeks, onions, garlic, tomatoes, celery, bananas, berries, oatmeal, flax, lentils and beans.

Though for quicker results you can buy some pro- and prebiotics, going natural is always the best way. Just cut some unnecessary unhealthy foods, reduce a little stress by getting 20 extra minutes of sleep and look out for these gut-boosting ingredients. Your stomach will thank you.

Sources: Creature Comforts, NIAID, Shawn Hoke, VancityAllie .com under Creative Commons