SIBO: Simple, Evidence‑Based Guide to Small Intestinal Bacterial Overgrowth

If you’ve been feeling bloated, gassy, or constantly tired after meals, you might have heard the term SIBO tossed around. That’s short for Small Intestinal Bacterial Overgrowth – a condition where bacteria that usually live in the colon multiply in the small intestine. The result? Digestion gets scrambled, nutrients don’t absorb well, and you end up with a whole pack of uncomfortable symptoms.

What Is SIBO and How Does It Show Up?

SIBO isn’t a rare mystery; it pops up in people with a history of IBS, low stomach acid, or anything that slows gut movement (like certain medications). The most common signs are:

• Recurrent bloating or abdominal distension
• Gas that smells especially foul
• Diarrhea, constipation, or alternating between the two
• Unexplained weight loss or difficulty gaining weight
• Fatigue that doesn’t improve with sleep

Because these symptoms overlap with many other gut issues, doctors usually run a breath test. You’ll drink a sugar solution, then blow into a tube every 20 minutes. A spike in hydrogen or methane signals that bacteria are fermenting the sugar too early in the small intestine.

Managing SIBO: Diet, Medication, and Lifestyle

Once you have a diagnosis, the goal is to trim down the bacterial load, restore normal gut motility, and keep the problem from returning.

1. Targeted antibiotics or herbal antimicrobials are the first line. Rifaximin works well for hydrogen‑dominant SIBO, while a combination of rifaximin and neomycin tackles methane‑dominant cases. If you prefer a natural route, compounds like oregano oil, berberine, or neem have shown promise in small studies.

2. Diet matters a lot. The Low FODMAP diet reduces fermentable carbs that feed the excess bacteria. Many people start with a two‑week elimination phase, then gradually reintroduce foods to see which trigger symptoms. Some clinicians also recommend the Specific Carbohydrate Diet (SCD) or a simple “SIBO Specific” plan that limits sugars, starches, and certain fibers.

3. Prokinetics help keep the gut moving. Drugs like low‑dose erythromycin or prescription agents such as prucalopride can prevent bacteria from stalling in the small bowel.

4. Nutrient support. SIBO can rob you of B‑vitamins, iron, and vitamin D. A basic blood panel can point out deficiencies, and supplementing with a quality multivitamin or targeted nutrients can boost energy while you treat the overgrowth.

5. Lifestyle tweaks. Stress management, regular physical activity, and proper sleep all support gut motility. Even simple habits like chewing food thoroughly and not lying down right after meals can make a difference.

Finally, keep an eye on weight. Because SIBO interferes with calorie absorption, many people with low body weight need a higher‑calorie, low‑FODMAP plan to maintain muscle mass. A weight‑based dosing calculator—like the ones we offer at Bodyweight Fitting—helps you match supplement doses to your current body weight, ensuring you’re not under‑ or over‑dosing.

Living with SIBO can feel like a constant guessing game, but with the right tests, a clear treatment plan, and a diet that respects your gut’s limits, most people see big improvements within a few weeks. If symptoms linger, revisit your doctor for a repeat breath test or a deeper look at underlying issues like motility disorders or pancreatic insufficiency.

Got questions about how your weight affects SIBO treatment, or need help choosing the right diet plan? Our site offers calculators, quick guides, and evidence‑backed advice to keep you on track without the jargon.