6 Gross Side Effects of Chewing GumChewing Gum May Increase Your Junk-Food Intake. Many people chew on a stick of gum to reduce food cravings and, theoretically, help them avoid eating unhealthy foods.It May Trigger TMJ (Temporomandibular Joint Disorder) in Your Jaw. Gastrointestinal Problems. Tooth Damage – Even from Sugar-Free Gum. Sheep Byproducts.