Was it a fluke?

Two days after the scale dipped below 160, it was back up again showing an 8 lb. gain. Was this possible? Since I am resding The Oz Principke about being accountable, I looked at what I ate over the two days rather than blame the scale. While I have determined that I do better (less to no snacking) on a high protein diet, some proteins are healthier than others. So, I'll stick to almond butter and kefir and skip the peanut butter and cheese. This causes a dilemma since PB&J is my favorite sandwich and I regard cheese as a spice. Well, now I know what I need to work on in the coming weeks/months.