Eating is a biological necessity that became a communal activity. If you have gotten used to eating popcorn at the movies with your family, you either have to avoid going to the movies or have the willpower to say no to the popcorn.

Not everyone can do it. The presence of friends, late night cravings or alcohol can make dieting difficult too. Research led by University of Birmingham sport and exercise scholar Heather McKee monitored the social and environmental factors that make people, who are following weight management programs, cheat. 

80 people who were either part of a weight-loss group or were dieting on their own participated in the one-week study. They were given mobile phones on which they kept an electronic diary of all the temptations that came their way, and the situations during which they gave in to these temptations. This helped the researchers to make a complete real-time record, known as 'ecological momentary assessment,' of participants' dietary temptations and lapses.

Participants lapsed just over 50 percent of the time when tempted, and were especially vulnerable at night. They were more likely to give in to alcoholic temptations than to eat a sugary snack or to overindulge. Their willpower was also influenced by the presence of others, regardless of whether a dietary temptation was unexpected or whether the dieter went looking for something to eat. The stronger the dietary temptation, the more likely a participant was to lapse. Not surprisingly, most participants reported that they were more aware of their eating behavior while keeping their diet diaries.

The findings could be valuable for dietary relapse and weight maintenance programs. They highlight the possible future use of mobile phone applications to support people who are dieting. Following a lapse in such programs, the findings also stress the importance of including specific coping mechanisms and reinforcing a person's self-efficacy, in other words, bolstering their belief in their own ability to reach their goals.

"The findings help piece together the complex jigsaw surrounding the daily predictors of dietary temptations and help us to better understand how dietary temptations and lapses operate," says McKee. "In the fight against obesity, we need to help people become more aware of the various personal, situational, and environmental factors that expose them to dietary temptations. In doing this, we can help them to develop the necessary skills to cope successfully with dietary temptations and prevent lapses."

Published in Annals of Behavioral Medicine.