Occasionally I get bored and to shake things up one afternoon, I laddishly announced to my unfortunate colleagues, "you know when you internally burp, sometimes it's like re-eating your meal all over again!" The girls groaned but being the curious cat that I am, it prompted further research.
Burping (also known as belching, ructus and eructation) is caused by the intake of air as you eat or drink and the subsequent need to expel it as gas. This expelled gas contains nitrogen, oxygen and stomach contents as the gastroesophageal junction does not produce a tight seal. So yes, ladies and gentleman by producing that internal burp, as opposed to vibrating your upper esophageal sphincter, you are indeed re-eating portions of your meal. Bon Appetit!