Hmm good question bellatrix because everyone is different. I only wish a certain set of foods seemed to work consistently but they don't always. However, there are a few drinks if you are having trouble meal planning.
Before I was diagnosed with celiac disease I kept snack bars with high fiber around. I went for high fiber breads and pastas as well. Can't do that as easily anymore now. However I keep nuts around b/c they are a quick fix for fiber, frozen veggies that can be tossed into a dinner plan in a pinch when I realize I haven't had enough, smoothies when I was out and about helped as well. Sweet and regular potatoes are great to toss in the oven too.
Some tips too:
It is also extremely important to have enough water so the colon can do it's job with fiber.
Ease up slowly on fiber.
Metamucil and Citrucel are good quick fiber supplements as well but be sure to check ingredients and avoid aspartame as it can cause more digestive issues. Flaxseed can be tossed into many things and ups the fiber. My sister mixes it into her oatmeal.
Pinterest has some good ideas and a few meal diaries:
https://www.pinterest.com/search/pins/? ... s&rs=typedOnce you get the hang of the meal planning more food becomes a lot of fun due to the creativity and branching out. :)