Diarrhoea can be a problem for anyone making changes to their diet. Acute diarrhoea may last 1-2 days and usually resolves on its own without any special treatment.
It is possible that changes you've made to your diet by starting on the IsoWhey program have caused a digestive disturbance. If you are mixing your IsoWhey with milk, you may be experiencing some intolerance to the lactose or casein in the milk, which can be difficult for some people to digest.
Other causes can include viral, bacterial, parasitic infections, reactions to medication, intestinal diseases, such as Crohns disease, Ulcerative Colitis and functional bowel disorders such as IBS (irritable bowel syndrome).
If your diarrhoea persists, stop taking your IsoWhey and consult with your healthcare practitioner.