A study published in the Obesity Journal suggests that obese people have a different physical response to food than average food eaters. Most of us don’t know the reasons why people overeat so, this study is a good source for us to realize why we sometimes eat more than what our body needs.

The study involved placing lemon juice and water on the participants’ tongues then measuring through cotton swabs the amount of saliva produced over time. It found out that most obese individuals salivate more than the usual. They have longer response to a new taste than those people with normal weight.

Dr. Bond, the study’s primary author says that: “Saliva production tends to decline in most people once they’ve gotten used to the taste of a certain food and had enough of it. The process, called habituation, is associated with a feeling of fullness.”

Because of this, obese people don’t get full quickly. “They’re not as sensitive to those feelings of fullness, and as a result, they continue to eat longer,” Dr. Bond said.

The study though small (34 obese people, 18 normal weight) could give way to further studies into physical reasons as to why obese people overeat.  Dr. Bond also said that saliva response is not the primary cause for overeating. We still don’t know whether obese people show different levels of saliva response before or after they gain excessive weight already.