Rapid eating can also cause discomfort after a meal. When you eat too fast, you introduce extra air into your digestive tract. This overloads your stomach, causing it to produce more acid. The result is heartburn, or what is technically known as gastroesophageal reflux disease (GERD). One study found that eating a meal in 5 rather than 30 minutes made people 50 percent more likely to have heartburn.