A moment on the lips can actually mean a lifetime on the hips, according to Swedish researchers, who found that binging on food seems to have a long term effect on body weight.
People who gorged on fast food for four weeks and did little exercise put on an average of 6.4kg of weight.
Two years later, signs of increased body fat were still apparent, says the Linkoping University study.
The Swedish researchers studied a group of 18 adults with an average age of 26.
During the study, the details of which were published in the journal Nutrition & Metabolism, the 18 participants had their physical activity limited to 5,000 steps per day, considered to be tantamount to a sedentary lifestyle.
Six months after increasing their intake of energy-dense food by 70%, the subjects had lost most of the weight gain, nearly 5kg.
Twelve months afterwards, however, their body weight had increased by 1.5kg.
At this point, the study also found an increase in fat mass (1.4kg) but no change in fat-free mass compared to the start of the study.
After two and a half years the average increase in body weight was 3.1kg.
A separate control group, which ate and exercised as normal during the study, did not show any change in body weight.
The study suggests that even a short period of excessive eating and a lack of exercise can potentially change a person's physiology - making it harder to lose and keep off weight.
Asa Ernersson, who led the research at the department of medical and health sciences at Linkoping University, Sweden, said: "The long term difference in body weight in the intervention and control groups suggest that there is an extended effect on fat mass after a short period of large food consumption and minimal exercise."
"The change of fat mass was larger than expected when compared to the controls.
"It suggests that even short-term behavioural changes may have prolonged effects on health," she said.