I'm no expert but I use flax seed on my yogurt fruit in the mornings and on salads etc I'm pretty sure that's high fibre, no idea if that's enough tho but I like how it tastes
I put some ground chia seed and cinnamon in my yoghurt. Ground chia has no discernible flavour whatsoever and once moistened is about the same consistency as they yogurt too. Chia is extremely high in fibre.
Not all high carb foods are high in fibre. I eat LOADS of greens. they contain little, but fibre and micronutrients. Cauliflower and brocolli are excellent for fibre.
Hana