After 5 years of learning how to control my colostomy output, at least as far as this is possible, here are the things that work for me:
If I want to thicken up my output I find that eating increased amounts bananas, oatmeal, nuts, rice and plain boiled potatoes all seem to do the trick. I know that a lot of people recommend marshmallows, but I have never liked those ultra-sweet mushy things, plus surely all that extra sugar in your diet can’t be particularly healthy? Unless you are keen on increasing your risk of developing type 2 diabetes…
On the other hand, if my output gets a bit too solid, which for me means an increased risk of ‘pancaking’ and subsequent bag leakage (or even a total ‘blowout’!), I reduce the healthy stuff in my diet (i.e. bananas, oatmeal etc) and indulge in some of what I would normally consider to be “rubbish” foods. For me this means anything with a high gluten content , such as bread, pasta and pastries, and anything that is artificially sweet (such as chocolate). Drinking more plain water than usual helps as well.
I tend to steer well clear of medications (such as Lomotil etc) that some people like to use to regulate their output. In my opinion they are probably best reserved for emergency situations rather than regular use.