How to Keep a Food Journal
You eat lunch. Two hours later you're bloated.
Was it the sandwich? The iced coffee? The stress of your 2pm meeting?
Without a record, you're just guessing.
That's where a food journal comes in. It's one of the first tools dietitians and doctors reach for when someone has stomach issues.
It's also how I found my own triggers and the reason I built My Tummi.
In this article I'll cover why a food journal matters, what to put in it, and the easiest ways to keep one.
Why keeping a food journal matters
Your memory isn't as good as you think
Quick. What did you eat last Tuesday?
Most of us can't answer that. And it's not just you.
People tend to under-record what they ate when they rely on memory at the end of the day, a point the NHS makes in its food diary guidance.
Writing it down as you go is simply more accurate than trying to remember. That accuracy lets you spot patterns you'd otherwise miss.
Symptoms don't show up on cue
Your stomach doesn't always react right away.
Sometimes bloating hits an hour after a meal. Sometimes it's the next morning.
A journal maps that timing. It lets you look back and connect today's symptoms to yesterday's dinner.
It's not always the food
Stress, poor sleep, and skipped workouts can all play a role.
That same meal might be fine on a Saturday and a disaster before a big presentation. A good journal captures both sides.
It helps you avoid cutting out too much
When your stomach acts up, it's tempting to blame a whole food group.
But it may only be a few specific foods causing the problem. A journal helps you narrow it down instead of giving up everything you love.
Your care team will thank you
Cleveland Clinic dietitian Devon Peart, RD, MHSc puts it simply: a food journal helps you connect foods to symptoms.
It also gives your care team the full picture. Every meal, every symptom, every bathroom trip.
That matters because memory plays favorites. We tend to blame whatever we already suspect.
You might be sure gluten is the problem. Your journal might point somewhere else entirely.
How long should you keep one?
Most guidance lands on two to four weeks.
Dietitians at London's Royal Free Hospital ask patients to include at least one weekend day. Weekends matter because that's when most of us eat differently.
What to put in your food journal
"The more detail you include, the more useful your food journal will be," says Peart.
Here's what that detail should look like.
1. Everything you eat and drink
Not just meals. Snacks, drinks, gum, supplements, and medications all count.
Kaiser Permanente's IBS diary asks you to note how much you ate and how it was prepared. Fried chicken and grilled chicken aren't the same thing to your gut.
Eating something packaged? It’s usually recommended to keep the packaging so a dietitian can see exactly what was in it.
2. The time
Write down when you ate and when symptoms started.
Without timestamps, you can't tell a reaction that took 30 minutes from one that took a day.
3. Your symptoms
What did you feel? Where? How bad was it?
"Bloated" is a start. "Bloated and crampy, 7 out of 10, lasted two hours" is much more useful.
4. Your bowel movements
Nobody wants to write about their poop.
But it's one of the most useful things you can track. The Bristol Stool Chart makes it easy by sorting stool into seven types:
- Types 1–2: a sign of constipation
- Types 3–4: healthy and easy to pass
- Types 5–7: a sign of diarrhea or urgency
Just write down the number. That's it.
5. Stress and mood
Your gut and brain are closely connected.
The IFFGD lists emotional state alongside diet and stool in its daily symptom diary for exactly this reason.
6. Sleep and exercise
A rough night or a skipped workout can change how your body handles food.
Kaiser's diary has a dedicated column for stress, sleep, and exercise.
7. Your cycle
If you menstruate, its recommended noting where you are in your cycle. Hormones can affect digestion too.
A quick note
A journal helps you find patterns. It doesn't diagnose anything.
Blood in your stool, unexplained weight loss, or diarrhea that wakes you up at night aren't typical of IBS. If you notice any of these, see a doctor rather than waiting for more data.
How to keep your food journal
The best food journal is the one you'll actually stick with.
Here are the most common options and where each one falls short.
Pen and paper
It's free and you can write whatever you want.
You don't even need to design your own. The IFFGD and Kaiser Permanente both offer free printable templates.
The downside? You have to carry it everywhere. And spotting patterns means flipping through weeks of handwriting.
Photos
Snap a picture before every meal. It takes two seconds.
But a photo doesn't tell you what's in the sauce or how much you ate. Your symptoms also end up somewhere else entirely, like a notes app.
Photos are a great memory aid. They're just not a full journal on their own.
Notes app or spreadsheet
A step up from paper since your phone is always on you.
Still, you're typing everything out by hand. And finding patterns is entirely up to you.
Calorie tracking apps
Apps like MyFitnessPal make logging food fast with barcode scanners and big food databases. I used one for years.
The problem is they're built for calories and macros. Not for bloating.
There's usually no good place to log symptoms or bowel movements. And they won't connect your meals to how you felt.
Gut health apps
Some apps are built specifically for digestive symptoms.
The Monash FODMAP app, for example, has a diary for food, IBS symptoms, bowel habits, and stress. It's great if you're following a low FODMAP diet.
Whichever you pick
Log as you go. Cleveland Clinic recommends recording food as you eat it or right after.
Waiting until bedtime is how details get lost.
Why I built My Tummi
I tried most of the options above. None of them did everything I needed.
So I built My Tummi to put it all in one place.
Logging takes seconds
Describe your meal or snap a photo. That's it.
My Tummi breaks it down into ingredients and food categories for you. You can still scan barcodes or search for foods if you prefer.
Food, symptoms, and stool in one journal
Log how you feel and your bowel movements right next to your meals.
No more piecing together a notebook, a photo roll, and a notes app.
It finds the patterns for you
This is the part paper can't do.
My Tummi looks for links between food categories and your symptoms. It also accounts for how long reactions take to show up.
When it spots a likely trigger, it sets up an experiment. You cut the food out, then bring it back, and see if your symptoms follow.
That's how I confirmed capsaicin and sugar alcohols were behind my bloating.
Share it with your care team
Seeing a dietitian or doctor? Share your journal with them.
Instead of trying to remember the last month, you can show them exactly what you ate and how you felt.
Give it a try
Keeping a food journal takes some commitment. There's no way around that.
But it doesn't have to be a chore. Try My Tummi and see what you can learn about your body.
If you have any feedback or questions, I'd love to hear from you. You can email me directly at arman@mytummi.app.