Quick answer: Bring a 1–2 week food and symptom diary that includes meal times, ingredients, portion sizes, bowel movements (with Bristol stool type) and symptom timing. Also bring recent test results (especially celiac screening), a list of medicines and supplements, notes on diets you've already tried, and your top goals. Don't cut out foods on your own before the visit unless your doctor has told you to.
A good IBS dietitian can save you months of guesswork. The first appointment usually goes to understanding how you eat now and how your gut responds. The more of that you bring in writing, the more of the session goes to an actual plan.
This guide is a packing list with reasons, plus a filled-in example of the food log dietitians find easiest to use.
Key takeaways
- The American College of Gastroenterology says the low-FODMAP diet's complexity calls for a trained GI dietitian [1]. Monash University recommends dietitian support through all three steps [2].
- Your most valuable item is a 1–2 week food and stool log with times, ingredients and Bristol types.
- Bring celiac test results if you have them. Don't go gluten-free before testing, because it can affect the results [4].
- Check credentials: "registered dietitian nutritionist" (RDN) is a legally protected title in the US [3]. "Nutritionist" generally isn't.
- Write down what you've tried and what you want from the visit.
Why see a dietitian for IBS or food intolerance?
A registered dietitian can help you change what you eat without over-restricting, which is the main risk of doing elimination diets alone. That matters most for the low-FODMAP diet.
The ACG recommends a limited trial of a low-FODMAP diet for IBS. It notes the diet's complexity, the risk of nutritional deficiencies from long-term over-restriction, and the time needed to teach all three phases properly. The guideline committee says this "requires the services of a properly trained GI dietician", while acknowledging that this point isn't itself evidence-based [1]. Monash University, which developed the diet, describes three steps: a low-FODMAP phase of 2–6 weeks under a dietitian's supervision, structured reintroduction to identify which FODMAPs trigger symptoms, then a personalized long-term diet [2]. It also stresses that the low-FODMAP diet "is not an elimination diet" [2]. The aim is to swap foods and then add back as many as possible.
RDN vs nutritionist. Registered dietitian nutritionists have a graduate degree from an accredited program, supervised practice and a national exam, and the RDN title is legally protected [3]. "Nutritionist" rules vary by state. When you book, ask: "Are you an RD or RDN, and how much of your work is IBS or digestive health?"
What should you bring to your first dietitian appointment?
Bring anything that shows what you eat, how your gut responds, and what's already been ruled out or tried. Use this checklist:
Your log
- 1–2 weeks of food, drink, bowel and symptom entries (details below)
- A one-page summary: typical day of eating, worst symptoms, any patterns you suspect
Medical information
- Your diagnosis, if you have one (such as IBS subtype, celiac disease, SIBO or lactose intolerance), and who made it
- Recent results: celiac blood test, iron, B12, vitamin D, thyroid, stool tests, breath tests, endoscopy or colonoscopy reports
- Referral letter or notes from your gastroenterologist or primary care doctor
- A list of medicines and supplements, including laxatives, antidiarrheals, probiotics, fiber supplements and protein powders
History
- Diets you've tried (gluten-free, dairy-free, low-FODMAP from an app, keto), for how long, and what happened
- Foods you already avoid and why
- Weight changes over the past year
- Anything that makes eating hard: shift work, cooking constraints, budget, cultural or religious food practices, a history of disordered eating
Goals and questions
- Your top three goals (for example, "less urgency at work", "eat out without fear", "stop living on rice and chicken")
- Questions, such as: Is low-FODMAP right for me? How long will each phase take? How will we test foods back in?
If you're also seeing a gastroenterologist, our gastroenterologist appointment prep guide covers the medical side of the same visit.
What should a dietitian food diary include?
A useful dietitian food diary records what you ate, how much, when, and what happened afterward, including your bowel movements. Detail on ingredients and timing is what lets a dietitian spot possible FODMAP load, portion effects or meal-timing issues. Food diary guidance from allergy specialists makes the same point: record every food and drink with its time, list the ingredients of mixed dishes, and include condiments, drinks and supplements [5].
Log bowel movements using the Bristol Stool Form Scale. It's a 7-point scale from type 1 (hard lumps) to type 7 (watery), and stool form tracks with how fast food moves through your gut [6]. It gives you and the dietitian a shared vocabulary.
Illustrative 2-day excerpt (example data, not a real patient):
| Time | Food & drink (with portion) | Symptoms (0–10) | Bowel movement | Notes |
|---|---|---|---|---|
| Day 1, 7:30 | Oat porridge (1 cup) with honey (1 tbsp), apple (1 medium), coffee with milk | — | 8:10 type 5 | Rushed morning |
| 12:45 | Wheat wrap with chicken, onion, garlic mayo; sparkling water | Bloating 5 at 14:30 | — | Desk lunch |
| 19:00 | Salmon, rice (1.5 cups), green beans; 1 glass wine | Cramps 4 at 21:00 | 21:40 type 6, urgent | — |
| Day 2, 7:30 | Sourdough toast (2 slices), eggs, tea | — | 8:00 type 4 | Slept 7 h |
| 13:00 | Lentil soup (2 cups), bread roll | Bloating 6 at 15:00 | 16:30 type 6 | — |
| 19:30 | Stir-fry with tofu, bok choy, rice; water | — | — | Period day 1 |
A dietitian can see a lot in this short excerpt: a possible link between bloating and onion, garlic or lentils, and a period-day note that may matter. Those are hypotheses to test with them, not conclusions. For a full template, see our IBS food diary guide.
How long? One to two weeks is usually enough for a first visit. Ask whether your dietitian wants you to keep going after the appointment.
What should you avoid before the appointment?
Avoid big, unsupervised diet changes in the weeks before. They make your baseline harder to read and can interfere with tests.
- Don't go gluten-free before celiac testing. NIDDK says doctors don't recommend starting a gluten-free diet before testing because it can affect test results [4].
- Don't stack eliminations. Cutting dairy, gluten and FODMAPs at once makes it impossible to tell what helped.
- Don't "eat clean" for the log. Eat as you normally do. The dietitian needs to see your real pattern, not your best week.
- Don't stop prescribed medicines without talking to the prescriber.
UK NICE guidance for adults with IBS starts with general advice, such as having regular meals and not leaving long gaps between eating. If symptoms persist, it says advice on exclusion diets such as low-FODMAP should only be given by a healthcare professional with expertise in dietary management [7]. That's a structured, supported approach, not a solo elimination spree.
What will the dietitian ask you?
Expect detailed questions about your eating pattern and how your gut responds. Common ones:
- What does a typical day of eating and drinking look like, including weekends?
- How often do you have bowel movements, and what Bristol types?
- Which symptoms bother you most, and when do they happen relative to meals?
- Which foods do you already avoid, and what happened when you ate them?
- How much fiber, fluid, caffeine and alcohol do you have?
- How do stress, sleep, exercise and your menstrual cycle affect things?
- What's realistic for you to cook, buy and eat?
Having your log in front of you turns most of these into quick look-ups instead of guesses.
How to track this before your dietitian visit
Start 1–2 weeks before the appointment and log in real time, because details fade fast. Each day, record:
- Every meal, snack and drink, with time, rough portion and main ingredients (a photo helps)
- Each bowel movement: time, Bristol type, urgency, straining
- Symptoms with a 0–10 rating and when they started
- Context: sleep, stress, exercise, period, eating out
If you use an app, inspect the actual record you plan to share and ask your practice which format it accepts. The Get Regular App tour and Doctor Report explanation describe the intended workflow; check current availability and the file itself before relying on it for a visit.
If you go on to do FODMAP reintroduction with your dietitian, our guide to tracking low-FODMAP reintroduction shows how to log each challenge.
When to see a doctor first
A dietitian is not the first stop for red-flag symptoms. See a doctor before, or as well as, a dietitian if you have:
- Blood in your stool, or black, tarry stools
- Unintentional weight loss
- Symptoms that wake you at night
- Persistent fever or vomiting
- Signs of anemia, or a low iron result
- New bowel symptoms later in life, or a family history of colorectal cancer, inflammatory bowel disease or celiac disease
The ACG lists blood in the stool, black stool, unintentional weight loss, older age at onset and a relevant family history as alarm features that call for medical evaluation [1].
FAQ
Do I need a diagnosis before seeing a dietitian for IBS? It's strongly recommended. Low-FODMAP is meant to manage medically diagnosed IBS [2], and celiac disease and other conditions should be ruled out first. Some dietitians accept self-referrals, but many will ask you to see a doctor first.
How long should I keep a food diary before seeing a dietitian? One to two weeks is usually enough for a first appointment, as long as it's detailed: times, ingredients, portions, bowel movements and symptoms. Ask your dietitian if they want a longer record.
Can I do the low-FODMAP diet without a dietitian? Some people try, but both the ACG and Monash recommend dietitian guidance because of the diet's complexity and the risk of over-restricting [1][2]. If you can't access a dietitian, ask your doctor for high-quality written materials, as the ACG suggests [1].
What happens at a first dietitian appointment for IBS? Expect a detailed review of your symptoms, medical history, typical eating pattern and food log, followed by a starting plan. That might be first-line diet changes, a fiber adjustment or a structured low-FODMAP phase, with a follow-up to review your response.
Sources
- Lacy BE, et al. ACG Clinical Guideline: Management of Irritable Bowel Syndrome. Am J Gastroenterol 2021;116:17-44. https://journals.lww.com/ajg/Fulltext/2021/01000/ACG_Clinical_Guideline__Management_of_Irritable.11.aspx
- Monash University. The 3 steps of the FODMAP diet. https://www.monashfodmap.com/blog/3-phases-low-fodmap-diet/
- Academy of Nutrition and Dietetics. About RDNs and NDTRs. https://www.eatright.org/about-rdns-and-ndtrs
- NIDDK. Diagnosis of Celiac Disease. https://www.niddk.nih.gov/health-information/digestive-diseases/celiac-disease/diagnosis
- Kids With Food Allergies (AAFA). Using a Food Diary to Sort Out Food Allergies. https://kidswithfoodallergies.org/living-with-food-allergies/new-food-allergy-diagnosis/diagnose-food-allergy-food-diary/
- Lewis SJ, Heaton KW. Stool form scale as a useful guide to intestinal transit time. Scand J Gastroenterol 1997. https://pubmed.ncbi.nlm.nih.gov/9299672/
- NICE. Irritable bowel syndrome in adults: diagnosis and management (CG61). https://www.nice.org.uk/guidance/cg61/chapter/Recommendations
This article is for general education and isn't medical advice. Get Regular is a tracking app — it doesn't diagnose or treat any condition. If you have red-flag symptoms or ongoing changes in your digestion, talk to a doctor.