Some common side effects of weight loss surgery include:
Constipation. Avoid granular fiber (Metamucil or psyllium). These can cause obstructions.
Dumping syndrome. Sugary food rushes through the stomach and can cause nausea, vomiting, and weakness.
Gallstones. Up to 50% of patients will form gallstones after gastric bypass surgery. Between 15% and 25% of people need surgery to remove their gallbladder after gastric bypass surgery.
Wound infections can happen up to 3 weeks after surgery. Symptoms include redness and warmth, pain, or thick drainage (pus) from the surgical wound. Wound infections require antibiotics and sometimes more surgery.