Weight management benefits from savouring meals

May 8, 2014, Tokyo Institute of Technology
Time courses of changes after eating 300-kcal meal. Filled and open circles denote data for the rapid eating and slow eating trials, respectively. * Significant difference, vs. resting baseline in slow eating trial. # Significant difference between rapid and slow trials

Researchers at Tokyo Institute of Technology use quantitative studies to identify significant correlations between thoroughly chewing food and the energy expenditure related to food digestion, absorption and storage.

The benefits of eating slowly and chewing thoroughly have been proposed for over a century. Now Yuka Hamada Hideaki Kashima and Naoyuki Hayashi have made quantitative studies of the relation between chewing and physiological parameters subsequent to a meal such as circulation and . As they point out "If chewing alters digestion-induced , its importance should be incorporated into weight management strategies."

The researchers based at Kyushu University and Tokyo Institute of Technology in Japan monitored 11 healthy normal-weight given 100 kcal of solid and 10 given 300 kcal of solid food. Both sets of subjects undertook two trials – one where they swallowed the food as rapidly as possible and one where they chewed as many times as possible.

The energy expenditure associated with digestion, absorption and storage of food, known as diet-induced thermogenesis, was significantly higher when the food was eaten slowly with a high number of chews. Previous research has indicated that increased orosensory stimulation increases this energy expenditure, which may be linked to the effects of leisurely and careful food consumption on diet-induced thermogenesis.

The researchers measured oxygen uptake and body mass to calculate the diet-induced thermogenesis and also monitored around the digestive organs by measuring artery diameters and blood velocities for 90 minutes after the food was taken. Correlations between different measured parameters suggest that the increased energy expenditure is associated with increases in the blood flow around the digestive organs.

"These findings suggest a partial link between obesity trends and chewing," they conclude. Further tests are needed to investigate responses to food that more closely resembles a regular meal with higher calorie content and greater variation in the nutritional content.

Previous studies on eating pace

Horace Fletcher (1849–1919) was among the early advocates for chewing slowly to prevent over eating and obesity. Subsequent research has substantiated his claims, demonstrating links between eating rapidly so that more than the required volume of food may be consumed before there is time to feel 'full'. However these observations had not been quantitatively studied in terms of number of chews.

Orosensory stimulation

Research into diet-induced thermogenesis after oral feeding compared with intragastric feeding has indicated that the orosensory stimulation during eating contributes to diet-induced thermogenesis. Yuka Hamada Hideaki Kashima and Naoyuki Hayashi suggest that the additional orosensory stimulation during eating slowly and chewing carefully may play a role in increasing diet-induced thermogenesis

Test subject details

The 11 test subjects in the 100 kcal trial were 25 years of age, 164 cm tall and weighed 56 kg (mean value). Seven were male and four were female. The 10 test subjects in the 300 kcal trial were all male, 25 years of age, 171 cm tall, and weighed 58 kg. They were all non-smokers with no food allergies, dental problems or oral cavity diseases, and were not taking any medication.

Physiological monitoring

The subjects were video recorded while eating and the number of chews counted. Oxygen uptake, respiratory exchange ratio, and minute ventilation were measured using a gas analyser on the subjects breath before and after eating Diet-induced thermogenesis was calculated from , body mass, and postprandial increments in energy expenditure above the fasting baseline.

The heart rates were determined using a standard electrocardiograph. The mean arterial pressure was monitored with an automatic sphygmomanometer applied to the subject's left middle finger. Simultaneous pulsed and echo Doppler ultrasound flowmetry was used to measure mean blood velocity and the vessel diameters of the celiac artery and superior mesenteric artery—two main arteries that supply oxygenated blood to the digestive organs.

Diet-induced thermogenesis and blood flow results

Diet-induced thermogenesis increased for slow eating and thorough chewing to 6 kcal and 10 kcal for subjects taking 100 kcal and 300 kcal, respectively. This compares with 0.2 kcal and 0.4 kcal, respectively for rapid consumption. While small the researchers highlight that over long periods and for larger quantities of food the difference could be significant.

The researchers also noted significant positive relationships among meal duration, the number of chews, accumulated diet-induced thermogenesis, and postprandial blood flow around the digestive organs. They conclude that chewing increases the diet-induced thermogenesis and blood flow, and further that the observed enhanced diet-induced thermogenesis is related to blood flow.

Explore further: Obese people feel full sooner than people of normal weight

More information: Hamada Y1, Kashima H, Hayashi N. "The number of chews and meal duration affect diet-induced thermogenesis and splanchnic circulation." Obesity (Silver Spring). 2014 May;22(5):E62-9. DOI: 10.1002/oby.20715.

Related Stories

Obese people feel full sooner than people of normal weight

April 8, 2014
Obese people take less time to feel full than those of normal weight. Despite this, they consume more calories. A faster speed of eating could play an important role in obesity, according to a study funded by the Swiss National ...

Central adiposity may blunt metabolism, worsen weight gain

December 3, 2013
(HealthDay)—In those with body mass index (BMI) greater than 29 kg/m2, awake and fed thermogenesis is reduced, and this change in energy balance predicts future weight gain, according to research published in the December ...

How tastes are linked with facial expressions

January 6, 2014
Researchers at Tokyo Institute of Technology identify links between the palatability of various tastes and circulation in different parts of the face.

Slower-paced meal reduces hunger but affects calorie consumption differently

December 30, 2013
Obesity rates in the United States increased from 14.5% of the population in 1971-1974 to 35.9% of the population in 2009-2010. It's believed that one contributing factor to expanding waistlines is the reported increase in ...

Eating little and often not as important as counting calories for weight loss

March 27, 2014
(Medical Xpress)—Eating small but frequent meals is often recommended for overweight adults trying to lose weight. However, research presented today at the Society for Endocrinology annual BES conference suggests that following ...

Recommended for you

Evening hours may pose higher risk for overeating, especially when under stress, study finds

January 16, 2018
Experiments with a small group of overweight men and women have added to evidence that "hunger hormone" levels rise and "satiety (or fullness) hormone" levels decrease in the evening. The findings also suggest that stress ...

Bariatric surgery prolongs lifespan in obese

January 16, 2018
Obese, middle-age men and women who had bariatric surgery have half the death rate of those who had traditional medical treatment over a 10-year period, reports a study that answers questions about the long-term risk of the ...

Sugar-sweetened drinks linked to overweight and obesity in children, adults: Analysis of new studies

December 23, 2017
A new review of the latest evidence on sugar-sweetened beverages (SSBs)- which includes 30 new studies published between 2013 and 2015 (and none of them industry sponsored) - concludes that SSB consumption is associated with ...

As income rises, women get slimmer—but not men

December 21, 2017
(HealthDay)—A comprehensive survey on the widening American waistline finds that as paychecks get bigger, women's average weight tends to drop.

Policy and early intervention can curb obesity rates

December 18, 2017
More information and emphasis on dietary lifestyle changes that prevent obesity, and its comorbidities, have not reduced the rise in obesity in U.S. adults and adolescents, according to a recent study in the New England Journal ...

Warning labels can help reduce soda consumption and obesity, new study suggests

December 15, 2017
Labels that warn people about the risks of drinking soda and other sugar-sweetened beverages can lower obesity and overweight prevalence, suggests a new Johns Hopkins Bloomberg School of Public Health study.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.