A new study published in the journal Obesity Surgery, suggests that very obese individuals have a different physical repsonse to food than that of normal weight individuals.

Most of us are completely baffled as to the reasons for overeating, and so this study proves an interesting read.

The study involved placing water then lemon juice on participant's tongues, and measuring (using cotton swabs) the amount of saliva produced over time. The researchers found that very obese people (all candidates for bariatric surgery) salivated for longer in response to a new taste, in comparison to those of a normal weight.

While this may not seem very significant, Dr Bond lead author of the study, explains:

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.

As a result, the obese individuals in the study were not likely to feel full as quickly. As Dr Bond goes on to say:

They're not as sensitive to those feelings of fullness, and as a result, they continue to eat longer.

This is interesting research, and could pave the way for further studies into physical reasons for a propensity to overeat. However, the study was small (34 obese people, 18 of normal weight), and as Dr Bond points out, the results don't necessarily suggest that the saliva response is the cause of overeating:

What we don't know is whether obese people show this different level of responding before they become obese, or if it is something that happens as you gain weight, and whether it changes with weight loss.

Study details: Differences in Salivary Habituation to a Taste Stimulus in Bariatric Surgery Candidates and Normal-Weight Controls.