...and have actually found it hard to lose weight whilst having major D as my body goes into panic mode and won't let go of any fat grams! Obviously, I'm heavier when I'm C, but that's just poop.
Using fitday.com has been VERY helpful for me....you do need to track your cals whatever you're doing weight-wise quite often with IBS as it's so easy to either eat just empty cals or too eat too few as it's all so low-fat. I've done both.
Btw, I'm 146 pounds and only 5'2, so I am NOT thin. I had lost 5 pounds, but then my Fibro flared again and I haven't lost any since.
Posts
I agree with Casey...
Obviously, I'm heavier when I'm C, but that's just poop. 
