How to track whether a gut habit is actually working

A few weeks into a new gut habit, most people reach the same shaky verdict: "I think it's a little better?" You started a walk after lunch, cut back on something, or added a supplement. Now you honestly can't say whether anything changed.

That isn't a personal failing. Digestive symptoms go up and down, and memory isn't a precise measuring tool. A simple tracking system solves most of that problem. Here's how to set one up.

Step 1: Choose one change and one question

Tracking works best when you test one thing at a time. Write the change and the question in a single sentence, such as: "Does a 10-minute walk after lunch reduce my afternoon bloating?"

If you start three new habits in the same week, you won't know which one helped, or which one caused a problem.

Step 2: Pick two or three simple measures

More isn't better. Choose measures you can record in under a minute:

• Bloating score. Rate it from 0 (none) to 10 (worst imaginable) at the same time each day, for example at 4 p.m.
• Stool form. Use the Bristol Stool Form Scale, a 7-point chart that runs from type 1 (separate hard lumps) to type 7 (entirely liquid). Types 1 and 2 are considered hard, 3 to 5 normal, and 6 and 7 loose (Blake et al., 2016).
• Bowel movement count. Simply tally how many you have each day.

Stool form is more informative than it sounds. In a Bristol study of 66 volunteers, stool form was more closely linked to how long food took to travel through the gut than bowel movement frequency was. When volunteers took a laxative or an anti-diarrhea medicine, changes in stool form tracked the changes in transit time better than changes in frequency did (Lewis and Heaton, 1997).

The scale is also reasonably easy to use. In a King's College London study, 169 healthy volunteers' stool type ratings matched up with the measured water content of their stools, and people correctly classified 81% of model stools. The trickiest calls were at the borders between types, such as 2 versus 3, or 5 versus 6 (Blake et al., 2016). So don't agonize over the exact number. Being consistent matters more.

Step 3: Record in real time, not from memory

Write it down the same day. In a study of 273 people with IBS, 89% of them women, participants rated their symptoms at the end of each day for a week, then tried to recall the whole week on day 8. As a group, they recalled some things fairly accurately, such as their worst pain and how often they had bowel movements. But other symptoms, like typical pain levels, were more vulnerable to recall bias, and a subgroup of people had trouble recalling accurately at all (Lackner et al., 2014).

A notes app, a paper calendar on the bathroom door or a simple spreadsheet all work. Choose the one you'll actually use.

Step 4: Get a baseline, then give the test enough time

Track for one to two weeks before you change anything. Without a baseline, you have nothing to compare against, and an unusually good or bad week can easily be mistaken for the effect of your new habit.

Once you start the change, keep everything else as steady as you reasonably can: meals, sleep, other supplements and activity. For most everyday habits, about four weeks is a reasonable minimum before drawing conclusions. If you're testing a probiotic, here's a realistic timeline.

Step 5: Decide in advance what counts as a real change

Researchers face this problem too. The IBS Severity Scoring System, a symptom questionnaire, gives a score from 0 to 500. In the study that validated it, a drop of 50 points reliably indicated improvement, and scores below 75 were in the range of people without IBS (Francis et al., 1997).

You can borrow that idea. Before you start, decide what would convince you, for example: "My average 4 p.m. bloating score drops by at least 2 points, and I have more days with type 3 to 5 stools." That's a personal rule of thumb, not a validated cutoff. Setting it ahead of time simply keeps you honest.

Step 6: Compare weekly averages

Daily numbers bounce around. At the end of each week, work out your average bloating score and count your bowel movements and stool types. Then compare the last week or two of the test with your baseline, not Monday with Tuesday.

If there's a clear improvement, keep the habit. If nothing has changed after a fair trial, that's useful information too. Drop it and test the next idea.

When to stop tracking and call a doctor

Tracking is for everyday symptoms, not warning signs. Don't wait out your experiment if you notice blood in your stool, black stools, unexplained weight loss, symptoms that wake you at night, or new bloating most days with early fullness, pelvic pain or urinary urgency. If you do see a doctor, bring your notes. A few weeks of real data are far more useful than "it's been bad lately."

Sources

1. Blake MR, Raker JM, Whelan K. Validity and reliability of the Bristol Stool Form Scale in healthy adults and patients with diarrhoea-predominant irritable bowel syndrome. Aliment Pharmacol Ther. 2016;44(7):693-703. PMID 27492648
2. Lewis SJ, Heaton KW. Stool form scale as a useful guide to intestinal transit time. Scand J Gastroenterol. 1997;32(9):920-4. PMID 9299672
3. Lackner JM, Jaccard J, Keefer L, et al. The accuracy of patient-reported measures for GI symptoms: a comparison of real time and retrospective reports. Neurogastroenterol Motil. 2014;26(12):1802-11. PMID 25424582
4. Francis CY, Morris J, Whorwell PJ. The irritable bowel severity scoring system: a simple method of monitoring irritable bowel syndrome and its progress. Aliment Pharmacol Ther. 1997;11(2):395-402. PMID 9146781

This article is for general information and isn't medical advice. Tracking is not a substitute for medical care, so talk to your healthcare provider about symptoms that are new, persistent or worrying.