Welcome to HCM! Is the blood bright red or dark red? The color will give you some guidance as to what you are dealing with. Bright red means the blood is coming from close to the anal reason with the most frequent cause being hemorrhoids. Occassionally, a change in diet will cause the hemorrhoids to flare up. Dark red blood is indicative of bleeding from higher up in the colon and more of a cause for concern. Did this bleeding start with this new diet you started? If so, discontinue diet, it sounds like a fad diet anyway and it is only by learning to eat for a lifetime that you can lose and maintain weight loss. Back to the bleeding . . . if it continues after you discontinue this diet, please call your doctor. With the blood as a symptom, I would want you checked for anemia (do CBC); you should have a rectal digital exam if the doctor feels necessary and you may need a colonoscopy. Definitely before a colonoscopy is considered you will be asked to give 3 fecal samples for lab to analyze for blood. Please feel free to come back to HCM for dietary advice after your doctor determines the cause of your bleeding. Ask him for a diet order and I can help you get started with it here. Send height, weight, desired weight, all labs and medications. Ask for Kathryn Shattler, MS,RDN