I have deeply contrasting , really light and really dark feaces , approx 50% of each in one deposit , is this anything to worry about ?

Probably not: Color of BM is almost always due to the type of food consumed. Meat meals, bismuth containing medications or consuming beets can make stools very dark, while those containing dairy or curry can be quite yellow. Consistently black tarry stools can be a sign of gastrointestinal bleeding. The 50/50 just means two foods of different types mixed in colon. Thanks for trusting HealthTap!