1. Fermented veggies made the ancient way with organic dirt-covered vegetables, ex. kraut, kvass, kim chee, kefir, etc. Read Sandor Katz.
2. Ancient heirloom potatoes, tubers, roots that are low glycemic index (or high if good insulin sensitivity) and ancient heirloom grains, legumes, lentils/dal that are low glycemic index (or high if good insulin sensitivity), prepared the ancient way (soaked, fermented, etc)
3. Soil-based probiotic 1-2 daily if not severely immune compromised (Bacillus licheniformis, Clostridium butyricum, etc)
4. Raw PS (potato starch) 1-3 Tbs + psyllium (if not allergic) 1-3 Tbs + high ORAC green powder (I like amazing grass, LOL) in 2 cups plenty of water
5. Exercise low-moderate intensity one hour daily continuously (10,000 steps) to move the gut/peristalsis and overcome broken myenteric musculo-neuro junctions
6. Avoid allergenic foods (corn, soy, gluten/wheat, dairy, nuts, egg whites, etc). Avoid GMO products and livestock/poultry fed GMO crops (corn, soy, etc).
7. Heal hormones and immunity -- take adrenal support, liver support, antioxidants etc (I use biocurcumin and berberine to combine with anti-microbials/anti-parasitics). This is particularly imperative for those with reactive hypoglycemia and BG crashes when they go longer than 3-4 hours between meals.
8. If the above fail, then you have more fastidious overgrowths and require 2-3 rounds of anti-parasitics/anti-microbials/anti-fungals. See what worked for my family and I HERE . If the above still does not fix SIBO, then consider mercury toxicity. Mercury saturates and kills microvilli in the small intestines and also disables enzymes including digestive enzymes.
(*hominids ate SGG small grass grains in the Paleo times fyi ~see Middle to Late Paleolithic: Neanderthals Consumed Grains and Legumes )