Is reactive hypoglycemia common in non diabetics?

No: Symptoms of hypoglycemia (shakiness, anxiety, palpitations, sweats) are common, but finding that the sugar is low causing these symptoms is very rare. Reactive hypoglycemia occurs in some prediabetics after eating very sweet foods. It can also occur in people who have had stomach surgery, due to a problem called dumping syndrome. Doing a glucose tolerance test is usually misleading.

Not so much: It is a response to hyperinsulinemia, which is the first step towards adult onset or type 2 diabetes. When one becomes obese, the body begins to ignore the message of insulin. The response in the pancreas is to secrete more insulin. When challenged with a meal the Insulin response is too much and when the meal is digested, there is still Insulin available but no food and the blood sugar drops.