I know that antibiotics, fake sugars, processed foods, getting older- all these things have an effect on your bodys ability to break down food and use it as its supposed to be used. Therefore you dont get the vitamins or nutrients you need. I have not had weight loss surgery (looking into it) and I am dealing with many of the same issues. Some of you may also take meds for heartburn which can also make the problems worse. I started taking HCL which is a digestive enzyme- My body isnt making enough acid to properly break down my food which is causing yeast overgrowth. You can use these- digestive bitters, a teaspoon of apple cider vinegar 30 min before meals- all of these are to help produce more acid to break foods down. When foods are not broken down properly they cause leaky gut, malabsorption, gut dybosis, yeast overgrowth and a whole host of other issues. Try it and see if it doesnt help get your yeast under control