The research team from Cornell University's Food and Brand Lab found that compared to normal weight diners, overweight individuals sat 16 feet closer to the buffet, faced the food, used larger plates, ate with forks instead of chopsticks, and served themselves immediately instead of browsing the buffet.
"What's crazy is that these people are generally unaware of what they're doing - they're unaware of sitting closer, facing the food, chewing less, and so on," said Brian Wanink, lead author of this study.
In the study involving 213 diners at 11 all-you-can-eat Chinese restaurant buffets, the researchers found that 27pct of normal-weight patrons faced the buffet compared to 42pct of obese diners.
Seventy one percent of the normal-weight diners browsed the buffet before serving themselves compared to 33% of obese diners.
The findings also revealed that 16pct of obese diners sat at a booth rather than a table compared to 38 pct of normal weight diners.
"When food is more convenient people tend to eat more," said coauthor Collin R. Payne, New Mexico State University.
"These seemingly subtle differences in behaviour and environment may cause people to overeat without even realizing it," he added.