I would agree with Slaney.
Normally your faeces is a mixture of waste products and water, however since all your digestion has had to deal with is the Ryveta grains, that is all it can work with, so it has extracted the moisture, and the grains are left, hence the 'flaky' consistency of your movement.
One you return to a nromal diet, your digestion will recommence its usual opertaions, and your faeces will return to normal - nothing to worry about.