Risks

The greatest risks of the gastric bypass diet come from not following the diet properly. If you eat too much or eat food that you shouldn't, you could have complications. These include:

• Dumping syndrome. If too much food enters your small intestine quickly, you are likely to experience nausea, vomiting, dizziness, sweating and diarrhea. Eating too much or too fast, eating foods high in fat or sugar, and not chewing your food adequately can all cause nausea or vomiting after meals.
• Dehydration. Because you're not supposed to drink fluids with your meals, some people become dehydrated. That's why you need to sip 64 ounces (1.9 liters) of water and other fluids throughout the day.
• Constipation. A lack of physical activity and of fiber or fluid in your diet can cause constipation.
• Blocked opening of your stomach pouch. Food can become lodged at the opening of your stomach pouch, even if you carefully follow the diet. Signs and symptoms of a blocked stomach opening include ongoing nausea, vomiting and abdominal pain. Call your doctor if you have these symptoms for more than two days.
• Weight gain or failure to lose weight. If you continue to gain weight or fail to lose weight on the gastric bypass diet, talk to your doctor or dietitian.