≡ Menu

Frequently Asked Questions About IBS Triggers (Part 2)

Welcome to part two of my frequently asked questions series! In my last post, we talked about frequently asked questions about IBS in general.  Today we’re going to discuss common questions about IBS triggers. Let’s dive right in!

What Triggers IBS Symptoms?

The first thing you should know is that every IBS patient is different. That means the things that trigger you are likely different than the things that trigger me. But, that being said, researchers have found a few things that impact a large number of people with IBS.

These triggers include poor sleep quality, not enough (or overly intense) physical activity, dehydration, stress, eating too much or too little fibre, eating general gut irritants (like coffee, alcohol, soda pop, chocolate, spicy foods, and greasy or overprocessed foods), or eating a diet high in FODMAPs or other dietary triggers.

You can read more about common triggers and the Low FODMAP Diet here!

What Is A Flare?

Each of us has a baseline for our daily bowel habits. This is what your bathroom habits look like from one day to the next. If you have IBS, your baseline might look like having 10 bowel movements a day, or nada for several days in a row. But, odds are, your “schedule” is relatively similar unless your IBS is giving you a ton of grief.

A “flare” is anything above and beyond your baseline symptoms. That means, if you normally go to the bathroom once every 3 days and you don’t go for 5 days, you’re having a flareup. If you normally go 5 times a day and you go 10 times, you’re having a flareup. If you normally have your symptoms under control, anything out of the ordinary is considered a flare.

How Do I Find Dietary Triggers?

Currently, the most effective way to test for dietary triggers is to remove the food being tested from your diet for 2-4 weeks. Then, try eating the food again and see if your symptoms return. This is an example of an elimination/re-challenge test.

This style of test can be used to test for lactose-intolerance, Celiac disease or non-gluten sensitivity, or to test a person’s sensitivity to FODMAPs or other common food intolerances.

If you or your healthcare team suspect you may have several food sensitivities, you might want to look into the Low FODMAP Diet. Unlike other elimination/re-challenge tests, the Low FODMAP Diet tests several common triggers at once. This means you can test several foods with only one elimination phase.

Click here to subscribe

Can I Take A Food Sensitivity Test to Find IBS Triggers?

The first thing you should know is that IBS symptoms and allergies are two separate issues. In people with IBS, some foods aren’t absorbed by the small intestine. So, they travel to the large intestine where they’re munched on by your gut bacteria. This kind of reaction ends when the “trigger food” has left the digestive system.

When you experience allergies, your immune system reacts to a normal food or material (like peanuts or seafood) and treats it like a pathogen (something that will harm your body). Your body releases antibodies to protect you and may trigger specific reactions in your body. Your reaction might be something annoying like hives, or something life-threatening like anaphylactic shock.

Food sensitivity tests claim they can spot food intolerances or “sensitivities” by checking for the antibody IgE in your blood. These antibodies are created by your immune system. But, research has shown IgE antibodies can be created just from being exposed to certain foods. Not necessarily as part of a negative reaction from your immune system. Most importantly, research hasn’t validated this as an accurate (or appropriate) method of testing for food sensitivities.

Also, because tests like this can show false positives, you may end up avoiding foods that don’t trigger your symptoms at all. While this isn’t always a problem for the general population, because our diets are already limited to our “safe foods” removing foods based on this type of screening can overly restrict your diet without any actual benefits.

Long story short, while a food sensitivity test can check for IgE antibodies, it can’t let you know what your IBS triggers are. You’re better off testing your food triggers using evidence-based programs like the Low FODMAP Diet.

How Long Does It Take for a Food to Trigger Symptoms?

If you’ve ever experienced IBS symptoms right after eating, it’s unlikely they were triggered by what you just ate. First of all, the majority of IBS issues happen in the colon (the last section of the intestine). It normally takes 4 hours or more for food you’ve eaten to reach the large intestine and start causing trouble. So what’s happening, then?

In a healthy person, it takes between 12 and 24 hours for food to travel the length of the digestive system. This means if you follow the average diet, you should have food in your digestive system at all times.

When you start eating, your body prepares your digestive system to receive new food. This includes warming up your gastric juices, sending instructions to various glands, organs, and nerves to start their digestive magic, and triggering your gastrocolic reflex.

Your gastrocolic reflex is a strong contraction of your intestinal muscles. It’s used to push food along your digestive tract to make room for new food. This can cause two issues. First, your muscles can push formed stools into your rectum to be released. This is why some people need to use the washroom right after eating.

Second, your gastrocolic reflex can push high FODMAP foods from previous meals into the colon. Once high FODMAP foods reach the colon, they may trigger IBS symptoms.

Click here to subscribe

Why Are My IBS Symptoms Worse on My Period?

Many women experience a flare-up of their symptoms during their period. When a woman’s body is preparing to menstruate, the tissue in the uterus creates a hormone called Prostaglandin. This hormone gives the uterus instructions to contract so it can shed the uterine lining. But, some of these hormones like to hike to the intestine where they continue to scream “squeeze” at the top of their little hormone lungs. In addition to that, during menstruation, the hormone Progesterone drops, which can lead to loose stools.

While most women will experience loose stools during this time, someone who is already prone to loose stools will likely have a noticeable increase in symptoms.

Why Does Excercise Make My Symptoms Worse?

While several studies have shown gentle to moderate exercise may improve symptoms in IBS patients, many people also experience exercise-induced symptoms.

There are a few reasons physical activity may cause your IBS symptoms to flare. For example, during high-intensity workouts, your abdominal wall can push on your stomach and intestines. This can cause issues like abdominal pain, cramping, or diarrhea. Your body may also release stress hormones during intense activities. This can lead to both diarrhea and constipation.

But, with that being said, there are lots of ways to incorporate physical activity in your life without triggering IBS symptoms. You can get more information on managing IBS and exercise here.

How Do I Tell the Difference Between IBS and the Flu?

Having IBS doesn’t make you immune to food poisoning, the flu, or any other illness or disease. So, how do you know if your symptoms are from IBS or the flu?

There are a few things to look for if you suspect your symptoms aren’t  IBS. First, if you’ve recently been around other people who are sick or if the people around you think they may be coming down with something, it might be the flu.

If you have watery and/or bloody diarrhea, nausea, or vomiting (and these aren’t part of your everyday symptoms) it’s probably the flu.

Side note: Unexplained blood in your stool always means doctor. No, Dr. Google doesn’t count.

If you’re feeling really tired, have muscle aches or you’re feeling weak in general, if you have headaches, feel light-headed or dizzy, or have a fever, it’s probably the flu.

Click here to subscribe

When Should I See My Doctor?

Sometimes your body will be out of whack and your IBS will flare. But, sometimes you’ll need a second opinion to make sure your symptoms are actually related to your IBS.

Always see your doctor if you have unexplained blood in your stool, if you’re having diarrhea or urgency in the middle of the night, if your symptoms suddenly shift from one side of the spectrum to the other, or if your symptoms suddenly become much worse as these can indicate something has changed in your body.

You should also go to the doctor if you develop a new symptom (like nausea, vomiting, joint pain, etc.) as this can be an indicator that something new is brewing.

Final Thoughts

Thanks for reading part two of my frequently asked questions series! In my next post, I’ll answer frequently asked questions about IBS symptoms. Don’t want to miss out? Sign up for my mailing list below and you’ll get a roundup of my monthly posts along with exclusive access to bonus content, VIP discounts, and some fabulous freebies! Together we’ll get the low FODMAP Diet down to a science!


  • Deiteren, A., Camilleri, M., Burton, D., McKinzie, S., Rao, A., & Zinsmeister, A. R. (2010). Effect of meal ingestion on ileocolonic and colonic transit in health and irritable bowel syndrome. Digestive Diseases and Sciences, 55(2), 384-391. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2900583/.
  • Gillan, K. (2018, April 18). How exercise can help your IBS. Retrieved from https://coach.nine.com.au/2018/04/18/12/00/irritable-bowel-syndrome-exerciseJohannesson,
  • E., Simren, M., Strid, H., MD, Ph.D., Bajor, A., MD, Ph.D., & Sadik, R., MD. (2011). Physical Activity Improves Symptoms in Irritable Bowel Syndrome: A Randomized Controlled Trial. The American Journal of Gastroenterology, 106, 915-922. Retrieved from https://www.nature.com/articles/ajg2010480.
  • Lavine, E. (2012). Blood testing for sensitivity, allergy or intolerance to food. Canadian Medical Association Journal, 184(6), 666-668. doi:10.1503/cmaj.110026
  • McNamara, L. (n.d.). Eating and IBS symptoms. Retrieved from https://www.monashfodmap.com/eating-and-ibs-symptoms/
  • Milne, V., Caufield, T., & Konkin, J. (2017, January 26). IgG tests promise to reveal food sensitivities. But are they science or science-ish? https://healthydebate.ca/2017/01/topic/igg-tests-science
  • Timing of symptoms and FODMAPs. (n.d.). Retrieved from https://www.monashfodmap.com/blog/timing-of-symptoms/

© 2018 Amy Agur – The FODMAP Formula


You might also like one of these:

5 Tips to Survive a Roadtrip with IBS Does the thought of hitting the road make you break into a cold sweat? Don’t panic! Try these 5 tips to survive your next road trip with IBS.

What are Probiotics and Prebiotics? Wondering if adding probiotics or prebiotics to your daily routine will help tame your IBS symptoms? Here’s the scoop on how these cheeky little bugs can help or hurt you.

What is the Low FODMAP Diet? Lots of people are talking about the Low FODMAP Diet these days. Have you ever wondered what it is? Check out this article for a deep dive into each of the three phases of the low FODMAP program and what it can do for you.


Let’s Get Friendly!