Current pathophysiological mechanisms of GERD in the obese encompass the following. 1) Mechanical: I) increased intra-gastric pressure: increased intra-peritoneal and abdominal wall fat mass increases the intra-abdominal and peri-gastric pressures with subsequent increased gastroesophageal pressure gradient "GEPE" with augmented esophageal acid exposure. Each BMI unit increase corresponds to a 10 percent increase in intra-gastric pressure. II) Hiatal Hernia: "HH" disrupts the integrity of the sphincter mechanisms and prolongs esophageal acid clearance. Thin, normal, overweight, and obese subjects have a 1.0, 1.9, 2.5, and 4.2 risk of having HH compared to thin subjects, respectively. 2) Motility: I) Increased Transient LES Relaxation "TLESR" are associated with acid reflux during the postprandial period, especially during inspiration. II) Low LES basal pressure: Increased prevalence of abnormally low LES basal pressure in the overweight and obese in comparison to the normoweight subject. III) Esophageal motility abnormality: Jaffin et al, with esophageal manometry, reported 61 percent of patients with altered esophageal motility from which 59 percent had altered visceral pain perception (asymptomatic). IV) Delayed gastric emptying: mostly associated with one of its major comorbidities, diabetes mellitus. 3) Esophageal sensitivity: Mercer et al., with a Bernstein test, found a significant difference between normoweight and obese subjects without clinical evidence of GERD (0 percent vs. 86 percent, respectively) for esophageal hypersensitivity. 4) Hormonal: mostly mediated by estrogen and adiponectin. 5) Environmental (Diet): high-fat, saturated fatty acids, high-cholesterol, and high caloric density diets have been associated with the highest likelihood of perceiving an acid reflux event; fat may confer its sensory effect by activating pain facilitatory pathways or by deactivating pain inhibitory pathways.