Eating is necessary for survival, but when food is used as a coping mechanism it can cause unintended consequences. eating

The problem with that is it can lead to obesity, which can trigger a vicious cycle since obesity can contribute to and be a source of chronic pain.

Studies show nearly 20 percent of the world's population lives with chronic pain, pain which lasts three months or more. Researchers wanted to know more about the psychology behind comfort eating in order to help develop pain management strategies to prevent the negative cycle.

"People who live with pain every day need to find ways of coping," said professor Toby Newton-John. "We think about medication, physical therapy or heat packs as pain management strategies, but we don't usually think about food in the same way. Yet two-thirds of our sample said they turned to food at least once a fortnight when pain flared."

Scientists surveyed 141 adults with chronic pain to understand why they turn to food. More than half (51.8 percent) said it was to have a pleasant experience, followed by half (49.6 percent) who said they used it as a distraction and 39 percent who said to reduce their emotions surrounding the pain.

"That was the somewhat unexpected finding," said Dr. Amy Burton. "Comfort eating wasn't just for the purpose of distraction or numbing negative feelings, although those were important too. For many, eating comfort foods provided a nice experience in their day and something to look forward to. If you're living with pain all the time, that moment of pleasure becomes a pretty powerful motivator.

"There may also be a biological explanation. Research shows high-calorie foods can have a mild pain-relieving effect. Even in animal studies, rats in pain will seek out sugar. It seems it's not just psychological. It's possible that there is a real analgesic property to these foods as well."

Therein lies the danger. Nearly 40 percent of the study participants met the definition of obese. And eating just to quell pain leads to weight gain and then each condition can make the other worse.

"In the short-term, high-calorie food makes people feel better," Newton-John said. "It reduces pain symptoms and enhances pain tolerance. Long-term, it can fuel weight gain and inflammation, which increases pressure on joints and makes pain worse; and that can trap people in a spiral that's very hard to break."

Click here to read more in the Journal of Clinical Psychology in Medical Settings.