Are you eating too much protein and not enough fat? That seems to cause some poor stools in people and it's far too common. Most of us try for at least 1g of fat to 1g of protein or more fat. Is this you?
If it isn't you might just have to give it some time to adjust. The more fiber one eats, the more their digestive system becomes dependent upon it and it can take some time to gain that function back.