What is junk food? Like porn, it can be hard to define, but most of us know it when we see it. A numbered scale from the University of Sao Paulo called the NOVA Food Classification System brings some clarity to the issue, and it lets a lot of junkish food off the hook. According to NOVA, not all processed food counts as junk, which is a relief, since the entire middle of the grocery store is piled high with processed food. Not all processing is bad. Taking peanuts out of the shell counts as processing but doesn’t affect their nutrient value.

The NOVA system places minimally processed foods like shelled peanuts in group one. Group two includes foods further refined from group one foods, like peanut butter or maple syrup. Group three includes foods that have added salt, oil, or sugar to preserve them, like bacon or canned sardines.

As long as these foods aren’t your major edibles, they are mostly fine. Group four, ultra-processed foods, is where we find the real junk food. In this group, it can be hard to locate any actual foodstuff, as with candy, margarine, fruity yogurt, and soft drinks. Note that supposedly healthy food—yogurt—is on the junk list because some versions are crammed with sugar.

These faux foods are dangerous to a healthy gut microbiota. They boost numbers of pathogenic bacteria which push out and kill the good bacteria. You should avoid these “foods” and tank up on healthy, fiber-filled veggies and fruit. But if you can’t get enough of these healthy foods into your diet, you can try a prebiotic supplement like Clarity Prebiotic Blend. It can help you balance your gut microbes and provide you with resilience against the stressors of modern life.

For more about how junk food can affect your gut, click here.