Respondents who ate up to 70 percent more calories than usual, and restrict the level of physical activity, have gained weight over six pounds. This weight could not be removed even after two and a half years later.

“Our research suggests that brief period of overeating may later have a long-term effects such as increased body weight and body fat in people of normal weight,” said Asa Ernersson from Linkoping University in Sweden, also the head of the research.

Her team followed 18 people, an average of 26 years old that have increased caloric intake by 70 percent and limited to 5000 steps per day over a period of four weeks. Before entering the study, subjects ate about 2270 calories a day, while during the investigation and ate up to 4000 calories .

Their diet was not healthy, and consisted mainly of fast food: hamburgers, pizza and French fries .The subjects were weighed and measured their body mass index before the start of the study, after four weeks, six months, one year and two and a half years later.

When their numbers compared with control group members (who did not increase the number of calories and were not limited in physical activity), researchers found that respondents from the first group accumulated 6.36 pounds in four weeks of overeating , and weight control subjects remained the same.

Six months later, people from the first group had lost about 50 percent of body weight, but still had too much weight. Even after two and a half years, respondents who ate daily almost 4000 calories were much heavier than at baseline. Their average weight rose from the initial 67.73 to 72.73 pounds.

“Given what we know, I think the best advice is to enter the food moderately and  engage in physical activity to maintain a healthy weight. Although it is sometimes difficult to avoid excessive enjoyment, such as certain holidays, it is important not to turn the event into a whole weekend “advised Alice Lichtenstein, professor of nutrition at Tufts University in Boston, who commented on the results of research published in the journal Nutrition & Metabolism.