Remove the bad. The goal is to get rid of things that negatively affect the GI tract such as inflammatory foods, infections, and gastric irritants like alcohol, caffeine or drugs. Inflammatory foods such as gluten, dairy, corn, soy, eggs and sugar can lead to food sensitivities.
I recommend food sensitivity testing to determine if any foods are a problem for you. Infections can be from parasites, yeast or bacteria. A comprehensive stool analysis is key to determining the levels of good bacteria as well as any infections that may be present. Removing the infections may require treatment with herbs and anti-fungal medication/supplements.