The dietary guidelines provided following surgery are essential for success. First and foremost, they are meant to allow your body to heal from surgery. Going forward, they are meant to help you lose weight appropriately. Any deviation from the dietary guidelines can result in a slow down in weight loss and sickness. “Dumping syndrome” – symptoms experienced when surgery patients eat too much or consume high-fat or high-sugar foods – can include fatigue, sweating, diarrhea, and vomiting.