I Have Been Having Loose Bowel Movements For The Last

I have been having loose bowel movements for the last 2 weeks. I am following a vegan plant based diet and this is very rare while I stick to my diet. I have been eating non diet food items on the weekends and think this may contribute to my loose bowel movements. However all my movements have been loose for this period of time even during the week while I am sticking to my diet. What do you think?