Why SIBO Breath Tests Are Fundamentally Unreliable: And How to Actually Identify What's Happening in Your Gut — Part 2: How to Actually Identify What’s Happening

The breath test is unreliable. So what do you do? You gather real, mechanistic data about your own gut using methods that correlate directly with your symptoms and your actual physiology. The Foundation: Symptom-Timing Mapping Before anything else, you need to understand the temporal relationship between eating and your symptoms. For 2 to 4 weeks, track the following: Immediately upon eating (0 to 5 minutes), note whether you feel immediate bloating or distension in your upper abdomen, whether you feel a warm or reactive sensation in your GI tract, and whether your appetite disappears even though you just started eating. These suggest rapid fermentation, possibly with bacterial overgrowth in the upper small intestine or proximal duodenum. Between 15 to 45 minutes after eating, track when bloating typically peaks, whether it&#8217;s localized (right upper quadrant, epigastrium, left lower quadrant) or diffuse, whether you feel pain versus distension versus pressure versus bloating, whether you have an urge to defecate or pass gas, and whether you burp and if so how many times and whether the burps smell putrid, sulfurous, or neutral. Peak bloating in this window suggests small intestinal fermentation, likely from dysbiosis in the jejunum. Between 2 to 4 hours after eating, note whether bloating continues or worsens, whether it shifts location from upper to lower abdomen, whether