I had constipation and after straining there was bright red blood on my toilet paper could the constipation be caused by me eating fruit and fiber and then eating a lot of carbohydrates and that cancelling out the fiber or is that wrong and i see doc?

Rectal blood: Rectal blood is abnormal and requires investigation as to cause. However, in your case if the blood was bright red, on the toilet paper and not mixed in with the stool, you can be reasonably certain of a benign cause like straining for a BM. To avoid constipation, drink adequate fluids daily and include adequate amounts of fiber in your diet daily. If bleeding recurs, see your MD for examination.