Hey there! I'm not a doctor, obviously, but I've had some problems with this too. You're right, straight fiber won't help by itself. You need to hydrate, like TONS of water. tons and tons. Fruits and veggies are good because they have water and fiber. Try to make everything you eat have a high water content (like soups, salads, etc.) Another key is probiotics. Any yogurt you can consume in your day will show you improvement. If you need to, ask your doctor about probiotic supplements. Some are sold over the counter, I think. They're helpful if you don't like yogurt too much. Also, I think if you do some yoga moves for improved digestion it can help a little. One example is to lay on your back, hug your knees to your chest. Then use your hands to rotate your knees in circles, first away from one another, then toward one another. The movement over your belly will help stimulate digestion. Also, you can try going for walks to encourage digestion after your meals.
These are all little tricks that might help after some time, but if you have a chronic issue with this, you may need to talk to your doctor about an enema or something like that. I've never needed to do that so I'm not sure. Good luck! Hope you feel better.
Lots and lots of water, warm water if you can, also everything the other poster said.
The other replies are exactly right. you can eat all the fiber you want but if you don't drink lots of water it won't do you much good. Try drinking about 12 cups a day and that should help soften things up so it can pass.
Several things can help, trick is finding out what works for you. I quite often get constipated and I find a good long walk can get things moving. When I was running, I had to make sure I went beforehand otherwise i was in trouble lol!
Also, over the counter glycerin suppositories are really good. They sort of grease everything up in there to ease the way lol! But only as a last resort if your natural laxatives and exercises don't work.
Finally though....If you are going for any length of time without a bm, please go back to your doctor. You don't want to end up having things get so compacted that you need surgery :(.
Without repeating what everyone else has said, you might want to try yogurt as well. It seems to help me---probably something about the probiotics and live active cultures.