I have IBS too, and this is a big worry for me as well. I am about to dump (haha) all the information and experience that I have. Take it as you will, I don’t mean to preach, just to say what I have done once before for a really big important moment, and what I will do again on my wedding day.
If you’ve never tried the FODMAP diet, you should. Raw fruit and veg can be healthy, but it can also mess with your digestion if you’re sentsitive to fructose and oligosaccharides. A lot of people try cutting wheat or dairy or meat but many don’t even question produce. I can tolerate FODMAPs when everything is going smoothly, but I cut them out prior to events or times when I know I will be nervous. FODMAPs also create a lot of gas in the intestines, so if you are gassy like me (lol, I look pregnant after I eat the wrong thing) get on that.
7 days prior I will cut all raw fruits and vegetables out of my diet. (Torture, as I love them, but VERY WELL COOKED ones are still ok, especially with beano.) I also cut out dietary supplements, ESPECIALLY anything with magnesium in it. Calcium is still OK, if you take it for your IBS-D, obviously.
At least 5 days prior, all red meat, dairy, alcohol, and caffeine, and will probably not eat much veggies at all after this point. I will take beano. (I like the ones that melt on your tongue.)
At 3 days prior, I begin to eat nothing but chicken (baked, skin on, as animal fats have been more helpful than harmful for me), some scrambled eggs, and LOTS of white rice porridge cooked in chicken broth with egg mixed in. That stuff is like a stomach miracle and so easy to make — just put rice in way too much water and way overcook it. It’s called “congee” or “jook” if you look for a recipe.
The night before, I will take an imodium before bed. This is important — for those of you who get nervous Bridesmaid or Best Man issues, this will help a LOT. Imodium in tablet form, in my experience, doesn’t fully kick in for up to a few hours, and a single booster before bed can really improve response time when you take one in the morning. For the most important times, I highly recommend a “before bed” dose.
This might be Too Much Information but about an hour before I take that dose, I use a glycerin laxative to make sure I don’t stop up anything that’s “on deck” that I might not be aware of. It doesn’t stay in the system, it’s in an out in 15 minutes or less.
Also, DO NOT USE GENERIC IMODIUM IF YOU ARE SENSITIVE TO DAIRY. Most generic imodium tablets contain a filler that has a dairy product that can make some people worse.
The morning of, I will eat rice porridge for breakfast and take another imodium. Again, just one. If it is a long time to the event, I will take one more 30-60 minutes prior. If you are desensitized or already know you need more pills, obviously use more. If this stops you up or you are worried that it will, you can reverse the effect gently and safely by either eating a lot of prunes/cherries, or taking a polyethylene glycol (Miralax) laxative AFTER the event is over. In small doses it is so gentle you may not even feel the effect for a day or so, so it won’t chain you to the toilet, but I’ve never had it fail.
I have only done this whole routine once. I’ve done parts of it numerous times for small events or trips here and there. When things are normal its not necessary, but when you have the compounding factor of anxiety, on top of everything else, and you absolutely MUST be sure that everything goes 100% perfectly and want to take no chances, it can’t be beat.