Bulsiewicz: Three self-checks for gut health and a tiered approach to common issues
Why bloating, constipation, and fatigue often share the same root long before any diagnosis
Dr. Will Bulsiewicz with Sarah Ann Macklin
Episode aired Mar 18, 2026·Page synthesised Jun 2, 2026·Last reviewed Jun 2, 2026
What this episode covers
- Many adults may have undiagnosed gut issues that quietly shape inflammation and long-term disease risk.
- Three useful self-checks are everyday symptoms, personal health history, and bowel-movement patterns.
- A stepwise approach starting with magnesium for constipation, then gradually increasing fiber diversity, then nurturing keystone gut bacteria like Akkermansia, may help alongside stress management and reduced ultra-processed food.
Why it matters
If the gut microbiome shapes inflammation, immune function, mood, cognition, weight, and long-term cancer risk, then early warning signs matter for many body systems at once. A large share of adults may have ongoing gut issues that never reach formal diagnosis, showing up as everyday symptoms rather than acute disease. Catching these patterns early and acting on the foundational levers (fiber diversity, hydration, magnesium where needed, stress management) may meaningfully reduce both daily discomfort and longer-term disease risk.
What stands out
- Nearly half of adults may have undiagnosed gut issues that show up as everyday symptoms (bloating, fatigue, irregular bowel habits, brain fog) long before any formal diagnosis is made.
- Three simple self-checks — symptom patterns, personal health history (antibiotic exposure, infections, stress periods), and bowel-movement regularity — can give meaningful information without expensive testing.
- Chronic constipation may create a self-perpetuating cycle: slowed motility allows fermentation byproducts to accumulate, which inflames the gut barrier, which slows motility further.
Best-supported action
The single highest-leverage move from this episode, anchored in the strongest evidence the speaker presents.
Track your bowel movements, digestive symptoms, and the variety of plant foods you ate for one week, then add 5 to 10 new plant foods to your weekly rotation if your current variety is below 20 different plants per week.
Where to start
Small low-friction starters covering the main moves from this episode.
- Track your bowel movements and any digestive symptoms for one week to spot patterns.
- Add 5 to 10 new plant foods (vegetables, fruits, beans, nuts, seeds, herbs, spices) to your weekly rotation.
- Add fermented foods like yogurt with live cultures, sauerkraut, or kefir to one or two meals per week.
Other supported actions
Further actions discussed in this episode, ordered from strongest to weakest evidence. This is one expert's view, the full topic compares and ranks across experts.
- Consider increasing your weekly plant diversity gradually toward a target of 30 different plants per week (vegetables, fruits, beans, nuts, seeds, herbs, spices), especially if your current diet is dominated by the same few staples, to support the microbial diversity tied to gut health and lower colorectal cancer risk over time.
- Consider adding fermented foods (yogurt with live cultures, sauerkraut, kefir, kimchi) to one or two meals per week, especially if your gut symptoms are mild but persistent, to support microbial diversity through direct food sources rather than supplements.
- Consider 200 to 400 mg of magnesium citrate or magnesium glycinate at bedtime for chronic constipation, especially if you have not had relief from increased fiber and hydration alone, with clinician supervision if you have kidney disease, are on heart or thyroid medication, or are pregnant.
Full context, impact ratings, and timing — available in related topics
Questions to take to your doctor
- Given my symptoms and family history, what specific gut testing (microbiome panel, calprotectin, colonoscopy timing) would meaningfully change what we recommend?
- Given my chronic constipation, would a structured 8-week trial of magnesium plus gradual fiber diversity be a reasonable first step before stronger interventions?
- Given my stress patterns, what role might gut-directed therapy or stress management play alongside dietary changes?
Full doctor prep with ranked questions available in the full topic page
Context
Board-certified gastroenterologist focused on gut microbiome health, fiber and plant diversity, and the gut-immune-brain axis. Tends to view gut health as a daily-input system shaped by food variety, stress, and lifestyle rather than a condition to fix once. Useful for the practical fiber-and-diversity framework and the mind-body integration; has commercial interests via 38TERA brand and related products, so weigh supplement-related recommendations with that context.
This does not prove fiber diversity or magnesium will fix any specific gut condition in any individual. The mechanisms discussed (microbial diversity, keystone species, gut-immune axis) are well-supported by research, but specific intervention effect sizes vary widely between adults. The speaker has commercial interests through 38TERA and related products; this does not invalidate the content but is worth knowing when weighing the strength of any supplement-related recommendations. This does not mean you should change or stop any current treatment for inflammatory bowel disease, celiac disease, or other diagnosed gut conditions on your own; coordinate with your gastroenterologist.
Where people go wrong
- Eating the same few 'healthy' foods every day for years and assuming diet quality is fine.Microbial diversity tracks plant diversity. A diet of the same five healthy foods may deliver fewer microbial species than a more varied diet of slightly less optimal foods. The fiber diversity matters as much as fiber quantity for many adults.
- Treating chronic constipation with aggressive laxatives before trying magnesium, fiber, and hydration.Stimulant laxatives may work short-term but often create dependency where the gut stops moving on its own. The stepwise foundational approach (magnesium, gradual fiber diversity, hydration) takes longer but typically restores normal motility rather than substituting for it.
What to expect over time
- First 2 to 4 weeksMany adults notice changes in bowel-movement patterns within the first 1 to 2 weeks of adding magnesium plus more fiber diversity. Bloating and gas may initially increase as the microbiome adjusts to new fiber sources; this is normal and usually eases within 2 to 3 weeks. The eating pattern shifts (more plant variety, fermented foods) become habit by the end of the first month for most people.
- Months 2 to 6Symptom patterns typically settle in months 2 to 6 as the microbiome stabilizes around the new inputs. Many adults notice improvements in energy, mood, and skin alongside the direct gut symptoms, reflecting the gut-immune-brain axis at work. Track at least one specific symptom that matters to you rather than judging by general well-being alone; specific tracking makes it easier to know whether the changes are actually helping.
- Year 1 and beyondLong-term, the bigger question shifts from symptom relief to maintaining gut health as life patterns shift (travel, stress periods, illness, antibiotics). Adults who maintain plant diversity and stress management tend to recover faster from gut disruptions and may have measurably lower colorectal cancer risk over decades. The work is less about a specific protocol and more about establishing daily defaults that compound over years.