My sister is suffering from digestive problems. It seems that certain foods cause her pain, nausea, and vomiting. Although it s been hard to pinpoint what food/foods it is. Her doctors have her on the FODMAP diet. They seem to think it is related to foods as all other medical conditions have been ruled out. My sister drinks a steady diet of regular mountain dew and has for many many years. Can this cause digestive problems? I ask because she told me she hasn t been sick in three weeks and she s had maybe 10 cans of Mountain Dew in that three-week span of time versus multiple cans every day. She s had digestive problems over the last four years that have been getting progressively worse. Currently she is 42 years old, 5 1 tall, and weighs 87 pounds. She s unable to put on any weight. If anything all she does is continue to lose weight. Any advice would be appreciated.