were you officially diagnosed with IBS?
Is your IBS alternating or the consitpation type?
Do you get pain or discomfort?
What tests have you had?
Part of this depends on why your losing weight, if its from not eating enough that is one kind of problem and if your eating enough and not gaining that is a red flag problem.
Another part of this is eating and not eating for long periods of time or not eating enough puts more strain and stressors on the gut.
I think there is quite a bit you can do and look into on all this for help.
I am not a doctor. All information I present is for educational purposes only and should not be subsituted for the advise of a qualified health care provider.
Please make sure you have your symptoms diagnosed by a medical practitioner or a doctor.