I feel like I've been "backed up" since I got pregnant with my first, almost 5 years ago. If I'm not really careful, I get really constipated. I think it's a combination of the iron in prenatals and breastfeeding like I do. Anyway, I don't know if it will help you much, but as long as I have a Green Smoothie every day, and keep away from carbs like pasta and heavy breads and such, I am fine. The green smoothie is the real lifesaver though. Yesterday I didn't have one, and things didn't go very well last night in the bathroom, if you know what I mean.
My Green Smoothie Recipe
1 Vitamix blender
Greens (spinach, lettuce, kale, etc.)
Supplements (magnesium, probiotics, etc.)
1/2 fill the blender with greens
Fill the rest with banana and other fruit, supplements, etc.
Add enough water for it to blend
Blend until smooth
It also helps with me not having much of an appetite, because I can just take little sips and get tons of nutrition in.