Eating too much food once in a while might give you occasional heartburn, but eating too much on a regular basis may give you gastroesophageal reflux disease (GERD). Johns Hopkins doctors explain why this happens.

With both obesity and GERD on the rise in the United States, medical researchers have wondered if a link exists between the two. The answer to this question appears to be "yes." An article in The American Journal of Gastroenterology examined the results of 20 studies involving more than 18,000 people with GERD. Overall, people who were overweight were 50% more likely to have GERD than normal-weight people; obese individuals were more than twice as likely.

Several theories may explain the link between GERD and obesity. For example, extra fat in the abdomen may increase pressure on the stomach and cause the lower esophageal sphincter to relax, allowing stomach contents to flow back up into the esophagus. In addition, body fat may release chemicals that decrease pressure in the lower esophageal sphincter or slow the clearance of acid from the esophagus.

Another possibility: Estrogen levels may play a role in the connection between obesity and GERD. One study found that obese women were more likely than obese men to have GERD; the risk was highest in premenopausal women and in postmenopausal women taking estrogen.

Whatever may be causing the increased risk of GERD in obese people, losing weight seems to help. An article in Archives of Internal Medicine found that losing weight and elevating the head of the bed were the only lifestyle measures that helped relieve GERD symptoms.

How much weight loss is enough? According to a study in The New England Journal of Medicine, decreasing BMI by 3.5 points (the equivalent of losing about 20 lbs) may significantly improve your GERD symptoms.