While most gastric bypass patients will experience this side effect within the first 18 months, the incidence of chronic dumping syndrome is 5–10%. Facial flushing, lightheadedness, fatigue, and postprandial diarrhea occur following consumption of sugars and processed starches.
You do not need to restrict yourself from the foods that you want. Just limit them from indulging too much. Which means to keep the balance of your foods to still get the right amount of nutrients that your body needs!