An end date, set on day one
The restrictive phase is capped at six weeks and the date is written the day it starts. There is no button that extends it. Guidance is four to six weeks and no longer (source).
Low FODMAP
Find out which foods actually bother you. Then get the rest back.
Low FODMAP is a short, structured test, not a diet you stay on. Loopa runs all three phases: a baseline, a restrictive stretch with an end date, and a reintroduction that tells you what really matters to you. Most people find it is only two or three things.
The point
The goal is the widest diet that keeps you comfortable.
Not the narrowest. Everything in Loopa pushes that way: the restrictive phase has a hard end date, the app celebrates the groups you bring back rather than the days you went without, and there is no streak anywhere for foods avoided.
It tells you when to stop
If your symptom score has not moved by the amount the research looks for, Loopa says so and helps you stop. It never suggests cutting out more. A drop of 50 points is the response the trials measure (source).
Most groups come back
People reacted to about two and a half of the six groups on average in a blinded study of reintroduction (source), so the expected outcome is that most of what you set aside returns.
How it works
Three phases, and the restrictive one is the shortest.
You are never asked to work out the plan yourself. Loopa knows which phase you are in, what it is for and what happens next.
1. Baseline, one to two weeks
Nothing is restricted. You eat as you normally would and log how you feel, so the rest of the protocol has something honest to compare against. Loopa will not flag a single food during this phase, on purpose.
2. Restriction, two to six weeks
You swap high-FODMAP foods for comparable ones, and Loopa checks meals for you and offers alternatives. At the end you answer five questions and find out whether it made a difference.
3. Reintroduction, then personalisation
One group at a time over three days, with a pause between, so a reaction can actually be attributed to something. That is the structure the practice literature sets out (source). What you tolerate comes back for good.
Before you eat
Check the plate, at the serving you are actually having.
Portion size is the whole thing here. Thresholds are defined per serving rather than per food (source), so the same cheddar is fine at 30 g and over the line at 150 g. Loopa answers for the one in front of you.
Small servings add up
Three things that are each fine on their own can be over the line together, so Loopa counts everything in the meal and anything you logged in the last three hours. When that is what happened, it says so.
One-tap swaps
Anything flagged comes with alternatives for the group that flagged it: scallion greens and chives for onion, rice or oat flour for wheat. Swap it and the check re-runs.
Never a hard no
“Log as planned anyway” is always there. Loopa gives you the reading and you make the call. Nothing in it stops you eating anything, or refuses to record what you ate.
It admits what it does not know
Loopa only uses published measurements. Where nothing covers a food, or a food has been measured for some groups and not others, it tells you it could not check it. That is never shown as a pass.
What you end up with
A tolerance profile, in your own words and your own numbers.
Six groups, and what your own log showed about each one, including the serving you were fine up to, where there was one. Every result describes your log rather than describing you.
Tested, not guessed
A result comes from a three-day challenge against your own baseline days. One heavier day is not treated as a verdict, because a quarter of people in the blinded study reacted to a placebo containing no FODMAPs at all (source).
Nothing is permanent
A group you reacted to is scheduled for a retest a few months out, and Loopa reminds you. Tolerance changes, and a result nobody revisits becomes a food you avoid for years on the strength of three days.
Everything else keeps working
Your meal plans, recipes, shopping lists and the AI coach all learn which phase you are in. Your diet style, allergies and never-eat list are untouched.
A report you can hand over
The phase timeline, your score against your own baseline, every challenge result and your tolerance profile, on one printable page for a clinician or dietitian. Learn more about your tolerance profile
What it is not
Four things people assume, and none of them is true.
Getting these wrong makes the diet harder than it needs to be, so Loopa is explicit about all four.
Not gluten-free
Wheat comes down for its fructans. Gluten is a protein and not a FODMAP. If coeliac disease has not been ruled out for you, testing is more accurate before you cut back on wheat (source).
Not dairy-free
The issue is lactose alone. Hard aged cheeses, butter and lactose-free milk all fit, and Loopa does not switch a dairy-free preference on for you.
Not low-carb
Rice, potatoes, oats and quinoa are all fine. A trial comparing the two head to head treated them as separate interventions (source).
Not a weight-loss diet
There is nothing in it that restricts calories, and Loopa shows no weight framing anywhere inside the protocol.
Before you start
A short check, and nothing about it is stored.
Before you can begin, Loopa shows five questions about your relationship with eating. Guidance is to look at restrictive eating before starting intensive diet therapy (source), and a protocol whose first phase is cutting things out is the wrong thing to hand somebody by themselves.
The answers are not kept
Not the answers, not a score, not the fact that the screen ran. There is no field in Loopa that could hold any of it. The only thing recorded is the date you completed it.
A supportive answer, not a lecture
If the check suggests this is better done with somebody alongside you, Loopa says so briefly and points you at a clinician. The rest of the app stays exactly where it was, and you can answer again whenever you like.
Common questions
Is this a diet I have to stay on?
No, and the app will not let you. The restrictive phase is capped at six weeks and the end date is set the day it starts. Published guidance is that this phase should run no longer than four to six weeks (source). After it, you bring groups back one at a time and end up on the widest diet that keeps you comfortable.
What if it does not work for me?
Then Loopa tells you so and helps you stop. If your symptom score has not come down by the amount the research looks for, the guidance is to stop rather than cut out more, and there is no path in the app that leads back into a stricter version. That is the published advice (source), and six weeks that changed nothing is genuinely useful to know.
How many foods will I end up avoiding?
Probably fewer than you expect. In a blinded study, people reacted to about two and a half of the six FODMAP groups on average, and a quarter of them reacted to a placebo with no FODMAPs in it at all as well (source). That is why Loopa does not treat a single bad day as a verdict.
Is Low FODMAP the same as gluten-free?
No. Wheat comes down because of its fructans, and gluten is a protein rather than a FODMAP. It is not dairy-free either: the issue is lactose, so hard aged cheeses, butter and lactose-free milk all fit. And it is not low-carb: rice, potatoes, oats and quinoa are all fine. Enrolling changes none of your other settings in Loopa.
Does the app know every food?
No, and it says so rather than guessing. Loopa uses published measurements, and where nothing published covers a food, or where a food has been measured for some FODMAP groups and not others, it tells you it could not check it. That is never shown as a pass.
Why does it ask about my portion size?
Because FODMAP content is dose dependent, and the thresholds are defined per serving rather than per food (source). The same cheddar is fine in a 30 g serving and over the line at 150 g, so every answer Loopa gives names the serving it is talking about.
I get constipated. Is this still for me?
It needs a little more care, and Loopa asks about it when you start. Real-world data on this diet shows improvement in pain, bloating and wind alongside a small increase in constipation (source). If you tell us that is your usual pattern, the app surfaces fibre and fluid guidance through the restrictive phase and leans its suggestions that way.
Do I need a dietitian?
It helps, and the guidelines say so. Working with a clinician and a dietitian familiar with gut conditions improves the odds (source). Loopa is built to make that easier, not to replace it: the report you can hand over is one of the things it produces.
Not medical advice
This is a tracking and testing tool.
Loopa helps you track and test. It does not diagnose or treat anything, and symptoms like these are worth a clinician’s look. Where your clinician or dietitian says something different from anything here or anything in the app, follow them.
Sources
- Lacy BE, Pimentel M, Brenner DM, et al. ACG Clinical Guideline: Management of Irritable Bowel Syndrome. The American Journal of Gastroenterology 2021;116(1):17–44. Read it
- Chey WD, Hashash JG, Manning L, Chang L. AGA Clinical Practice Update on the Role of Diet in Irritable Bowel Syndrome. Gastroenterology 2022;162(6):1737–1745. Read it
- Nybacka S, Törnblom H, Josefsson A, et al. A low FODMAP diet plus traditional dietary advice versus a low-carbohydrate diet versus pharmacological treatment in irritable bowel syndrome (CARIBS). The Lancet Gastroenterology & Hepatology 2024;9(6):507–520. Read it
- Van den Houte K, Colomier E, Routhiaux K, et al. Efficacy and Findings of a Blinded Randomized Reintroduction Phase for the Low FODMAP Diet in Irritable Bowel Syndrome. Gastroenterology 2024;167(2):333–342. Read it
- Varney J, Barrett J, Scarlata K, et al. FODMAPs: food composition, defining cutoff values and international application. Journal of Gastroenterology and Hepatology 2017;32(Suppl 1):53–61. Read it
- Whelan K, Martin LD, Staudacher HM, Lomer MCE. The low FODMAP diet in the management of irritable bowel syndrome. Journal of Human Nutrition and Dietetics 2018;31(2):239–255. Read it
- Rej A, Sanders DS, Shaw CC, et al. Efficacy and Acceptability of Dietary Therapies in Non-Constipated Irritable Bowel Syndrome. Clinical Gastroenterology and Hepatology 2023;21(12):3067–3078. Read it