Tea at mother-laws

We regularly have tea/supper at my mother-in-laws on Sumdays. She loves to bake for others. Over time I've learned to take fruit and oatcakes, but I still end up eating cakes or buns or scones every time. And then I feel rubbish later or on Monday mornings. I'm feeling very fed up about it, like I'm not good at taking care of myself. :-( thanks for reading.