Many researchers and experts have suggested that one contributing factor to the ever expanding waistline of our global population is an increase in energy intake, which may be associated with the speed at which we eat. One theory suggests that eating too fast can impair the relationship between the sensory signals and processes that regulate how much we eat - therefore causing is to eat more.
Writing in the Journal of the Academy of Nutrition and Dietetics, a team of US-based researchers examined the relationship between eating speed, feelings of hunger and energy intake during a meal in both normal-weight and overweight or obese people.
Led by Professor Meena Shah from the Texas Christian University, the team found that eating slowly led to lower hunger ratings in both overweight and normal-weight groups. However, only normal-weight individuals were found to have a statistically significant reduction in calorie intake.
"Slowing the speed of eating led to a significant reduction in energy intake in the normal-weight group, but not in the overweight or obese group," said Shah. "A lack of statistical significance in the overweight and obese group may be partly due to the fact that they consumed less food during both eating conditions compared to the normal-weight subjects."
"Slowing the speed of eating may help to lower energy intake and suppress hunger levels and may even enhance the enjoyment of a meal," she said.
Shah and her team asked a group of normal-weight subjects and a group of overweight or obese subjects to consume two meals in a controlled environment. All subjects ate one meal at a slow speed, for which they were instructed to imagine that they had no time constraints, take small bites, chew thoroughly, and pause and put the spoon down between bites, and a second meal at a fast speed, for which they were instructed to imagine that they had a time constraint, take large bites, chew quickly, and not pause and put the spoon down.
The team collected data on caloric consumption in addition to feelings of hunger and fullness and water consumption before and after both the fast-paced and slow-paced meals.
Analysis of their data revealed that only normal-weight subjects had a statistically significant reduction in caloric consumption during the slow compared to the fast meal: with an 88 kcal reduction for the normal weight group, versus a non-significant 58 kcal reduction in the overweight or obese group.
Despite these differences in caloric consumption between the normal-weight and overweight and obese subjects, the team did reveal some similarities, with both groups reporting that they felt less hungry later on after the slow meal than after the fast meal.
"In both groups, ratings of hunger were significantly lower at 60 minutes from when the meal began during the slow compared to the fast eating condition," added Shah.
"These results indicate that greater hunger suppression among both groups could be expected from a meal that is consumed more slowly."
In addition, both the normal weight and overweight or obese groups consumed more water during the slow meal, the team added - noting that a higher intake of water could lead to also play a role in the increased feelings of fullness.
Source: Journal of the Academy of Nutrition and Dietetics
Published online ahead of print, doi: 10.1016/j.jand.2013.11.002
"Slower Eating Speed Lowers Energy Intake in Normal-Weight but not Overweight/Obese Subjects"
Authors: Meena Shah, Jennifer Copeland, Lyn Dart, et al