How to track your gut at home

Most expensive gut tests give you a stack of data and no clear next step. Cheap home tracking gives you fewer numbers but each one tells you what to change. Here's a practical 2-week protocol that works.

What to track each day

1. Stool form: Bristol stool scale 1-7. Type 3-4 is the healthy zone.
2. Bowel movements per day. 1-3 is normal. Less than 3 a week is constipation territory; more than 3 a day is diarrhoea territory.
3. Bloat: 0 (none) to 10 (maximum), measured at three points, waking, 6pm, bedtime.
4. Fibre: rough grams. 30 g per day is the UK target for adults (NHS / SACN).
5. Fermented food: yes/no. Yoghurt, kefir, kimchi, sauerkraut, miso, kombucha, sourdough.
6. Sleep: hours and quality (rested vs tired).

The corn test (do it once)

Eat a portion of sweetcorn at lunch on day 1. Note the time. Watch your stool. Note when you first see corn kernels, this is your gut transit time. The healthy range is 12-48 hours, with most adults sitting around 24-36. Less than 12 means fast transit (often loose stools); more than 60 means slow transit (often constipation).

Patterns to watch for

Healthy

• Bristol type 3-4 most days.
• 1-2 movements daily.
• Bloat under 3 most evenings.
• Fibre at or near target.
• Fermented food 4+ times a week.
• Transit time 24-36 hours.
• Sleep 7+ hours.

Slow gut pattern (often constipation)

• Bristol type 1-2 (hard, lumpy).
• Fewer than 3 movements per week.
• Transit time over 60 hours.
• Bloat builds through the day.
• Often paired with low fibre or low water intake.

Fast/sensitive gut pattern (often IBS-D or food intolerance)

• Bristol type 5-7 (loose, watery).
• Multiple movements daily, often urgent.
• Transit time under 12 hours.
• Strong bloat after specific meals.
• Often paired with stress or specific FODMAP foods.

Cycle-driven pattern (women)

• Bloat correlates with cycle day, not food.
• Constipation in the luteal phase, sometimes loose stools at the start of bleeding.
• Pattern repeats month after month.
• Track menstrual cycle alongside the gut data.

What to do with the patterns

1. Slow gut pattern: add 5 g of fibre per day for a week, drink 2 litres water, walk 30 minutes daily, magnesium citrate 400 mg before bed if needed.
2. Fast/sensitive gut: try a low-FODMAP elimination under a dietitian. Check for bile acid diarrhoea if loose stools dominate.
3. Bloat builds through the day: stop eating 3 hours before bed, walk after meals, check evening sodium.
4. Bloat correlates with cycle: see the luteal-phase bloating guide. Adjust week-by-week instead of daily.
5. Sleep under 7 hours and gut symptoms worse: prioritise sleep first. Many gut issues are downstream of sleep debt.

When home tracking isn't enough

• Blood in stool or stools that look black and tarry.
• A persistent change in bowel habit that doesn't settle (especially over 50).
• Unexplained weight loss alongside gut symptoms.
• Pain that wakes you at night.
• Family history of bowel cancer or inflammatory bowel disease.
• Iron-deficiency anaemia on a routine blood test.