Food digestion begins in the mouth, which is why how you chew your food can have an impact on not only digestion, but weight as well.
Chewing causes the mechanical breakdown of large food molecules into smaller particles. This increases the surface area of food exposed to digestive enzymes, such as salivary amylase that begins the digestion of carbohydrates in the mouth. A lingual lipase is also released in the mouth to begin the breakdown of fat.
How long do you chew your food?
Now, think about how long a bit of food stays in your mouth. Is it basically one or two bites and you’re swallowing? If so, does that give the digestive enzymes salivary amylase and lingual lipase very much time to do their job? Does that give you adequate time to break your food down into small particulars for increased surface area exposure? If you are like most people, probably not.
How does chewing impact your weight?
A study out of China, published in the September 2011 issue of the American Journal of Clinical Nutrition, compared the effects of chewing on calorie consumption and hormone production.
The small study observed the chewing habits of 16 normal weight young men and 14 obese young men.
The obese group was found to have a lower average number of chews per bite of food versus the normal weight group. Participants in each group had bite sizes of a comparable size, but the obese group chewed each bite an average of 15 chews per bite, while the normal weight group had an average of 40 chews per bite.
Researchers found that the participants who had a higher number of chews per bite tended to consume a lower amount of food overall. The normal weight group with an average of 40 chews per bite consumed 12% less food than the group averaging 15 chews per bite.
The number of chews per bite was also impacted hormones connected to appetite. The three hormones evaluated in this study include postprandial ghrelin (a hormone that stimulates appetite), postprandial glucagon-like peptide 1 (signals satiety), and cholecystokinin (a hormone that reduces appetite). More chews per bite resulted in reduced ghrelin concentration, increased glucagon-like peptide 1 levels, and increased cholescystokinin concentrations.
These findings indicate that the more you chew your food the more satisfied you’ll be and the more your appetite will be reduced.
This goes along with the common guidelines to chew your food thoroughly, eat slowly, and expect is to take ~20 minutes for your stomach to tell your head it’s full. By following these guidelines you’ll likely consume fewer calories and maintain a lower weight.
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All the best,
Lisa Nelson RD