Bariatric surgery can have both positive effects on health and potential side effects. The specific side effects can vary depending on the type of bariatric surgery performed, but here are some common ones:

Surgical risks: It includes infection, bleeding, blood clots, and adverse reactions to anesthesia.

Nutritional deficiencies:It impacts nutrient absorption and lead to deficiencies of iron, vitamin B12, calcium, and vitamin D. These deficiencies may require lifelong supplementation and close monitoring.

Dumping syndrome: Can occur after gastric bypass surgery, where food moves too quickly from the stomach to the small intestine. You may experience nausea, vomiting, diarrhea, dizziness, and rapid heart rate after meals.

Gallstones: Rapid weight loss after bariatric surgery can increase the risk of developing gallstones. 

Changes in bowel habits: Some individuals may experience changes in bowel movements like diarrhea or constipation, after bariatric surgery.

Hair loss: Temporary hair loss or thinning may occur due to nutritional deficiencies or rapid weight loss. This is usually temporary and can be managed with proper nutrition.

Psychological and emotional changes: Bariatric surgery can have a significant impact on body image, self-esteem, and emotional well-being. Some may experience depression, anxiety, or body image issues post-surgery.