People who eat meals or snacks while watching TV, playing
games or reading tend to consume more kilojoules in a sitting, and especially
later in the day, according to a review of two dozen past studies.
"Some studies have individually shown this before, but
the evidence has never been put together," said lead author Eric Robinson
from the University of Liverpool, UK. According to Robinson, distracted eating
could increase the amount of food consumed by up to 50%.
How the study was
On the other hand, summoning memories of what was eaten in a
previous meal decreased the amount of food eaten later."Even though we
make decisions about what and when to eat with apparent ease all the time,
these decisions are actually very complex and can be easily disrupted,"
Suzanne Higgs, a study co-author and psychologist at the University of
Birmingham in the UK, told Reuters Health in an e-mail.
broadly categorised eating patterns as "attentive," such as sitting
quietly and recording what was eaten during a meal, or the exact opposite,
"distracted." Distracted eaters do not pay close attention to food
and are not as aware of how much they have eaten.
Robinson and his colleagues searched the scientific
literature and found 24 studies conducted between 1997 and 2011 that met their
main criterion of involving an experimenter who actively manipulated
participants' attention, memory and awareness of eating food.
What the previous studies
All of the studies were tightly controlled and monitored,
but each had different methods of manipulating participants' attention and
awareness. For example, in one study, adult men and women watched television
while eating. In another, participants snacked on pistachio nuts and
experimenters immediately removed the nut shells from view.
The experiments ranged in size from 14 participants to 122,
and 18 of the 24 studies were done with university students as subjects. Nearly
all of the men and women in the experiments were normal weight, rather than
overweight or obese.
The analysis suggests statistically significant differences
between participants who ate attentively and those who ate while distracted,
Higgs said. On average, eating while distracted increased the amount eaten by
about 10%, compared to not being distracted. But it also increased the amount a
person ate at a later meal by more than 25%.
after food consumption
In contrast, enhancing memories of food consumed at an
earlier meal reduced the amount consumed at a subsequent meal by about 10%.
Enhancing awareness of the food being consumed at the current meal did not,
however, change how much people ate at that meal.
Still, in light of
the overall results, the authors think that attentive eating techniques could
be incorporated into weight loss regimens as an alternative to intense
calorie-counting. Robinson said these findings could be used, for instance,
toward developing a mobile-phone "app" that prompts people to eat
with more attention and awareness.
Practices similar to attentive eating have been a part of
behavioral therapy weight loss programs for decades, said Michael Lowe of
Drexel University, who was not involved in the new study. "The learned
habits tend to dissipate after the program ends and most individuals regain the
weight they lost," Lowe said. For example, what works for a person in the
normal weight range may not work for an obese individual, possibly because
cognitive processes may differ between the two, Lowe said.
Robinson and Higgs have already begun to look at distracted
and attentive eating patterns among overweight and obese participants, but the
study is ongoing.
"The findings, strictly speaking, only apply to those
in the normal weight range," Lowe said of the current study. He added,
"Even if you use the same laboratory setting, it's difficult to know if
these same interventions would apply to obese individuals.""There are
some additional big steps before it's plausible that these findings could
ultimately help people keep their weight off," Lowe said.