Hi, I have ulcerative colitis but have been in remission for a good number of years. When I switched to Huel, I started with just one shake a day to see how it would settle. No issues at all and have been on Huel 3 times a day for over a year now with no problems.
As Linuxgeek says, everyone is different so if you want to give it a go, do it gradually. A sudden drastic change in diet could well trigger a flare, so one a day to adjust if you intend on using more.
My health has been so much better since the switch. I firmly believe my extended remission is a combination of cutting out many of my trigger foods (bagels was a random one) as well as getting down to a healthier weight.
If you are still concerned, check with your GP or IBD nurse if you have one appointed to you.