The combination of eating quickly and eating until full trebles the risk of being overweight, according to a study published today on bmj.com.
Until the last decade or so most adults did not have the opportunity to consume enough energy to enable fat to be stored. However, with the increased availability of inexpensive food in larger portions, fast food, and fewer families eating together and eating while distracted (e.g. while watching TV), eating behaviours are changing, and this may be contributing to the obesity epidemic.
Professor Iso and colleagues recruited over three thousand Japanese men (1,122) and women (2,165) aged 30-69 between 2003 and 2006 to examine whether eating until full and speed of eating are associated with being overweight. Participants were sent a diet history questionnaire about their eating habits including questions about eating until full and their speed of eating.
The researchers report that around half (50.9%) of the men and just over half (58.4%) of the women said they ate until they were full. And just under half (45.6%) of men and 36% of women said they ate quickly.
The group of participants who said they ate "until full and ate quickly" had a higher body mass index (BMI) and total energy intake than those who did not "eat until full and did not eat quickly".
The researchers also found that both men and women in the "eating until full and eating quickly" were three times more likely to be overweight than the participants from the "not eating until full and not eating quickly" group.
The authors conclude that a combination of eating until full and eating quickly has "a supra-additive effect on overweight".
These findings demonstrate how current eating patterns may contribute to the current epidemic of obesity, say Elizabeth Denney-Wilson from University of NSW and Karen Campbell from Deakin University in Australia, in an accompanying editorial.
They call on doctors to work with parents to encourage healthy eating habits in their children like eating slowly, serving appropriate portion sizes, and eating as a family in a non-distracting environment.