A study published in Appetite in 2011 found that eating speed had a direct correlation on weight gain.
We all might guess, quick eaters tend to consume more calories than slow eaters do. Slowing down allows us to fully chew our food, which allows our bodies time to control our ” I’m full” hormone, ghrelin, so that we know when we are full. A study in 2011 American Journal of Clinical Nutrition found that test subjects who chewed 40 times versus 15 times ingested 11.9% less food.
There’s more. The body needs about 20 minutes to generate “chemical” feelings of satiety. Let’s outline the basics: we have hormones that regulate body weight (leptin and insulin) and ones that control appetite (like ghrelin and cholecystokinin). Turns out that obese and normal-weight folks differ in their levels of and responses to these hormones—obese folks tend to have lower levels of the hormones that control appetite and higher levels of those that promote fat storage. By eating too quickly, the body is unable to regulate these hormones fast enough to do their job and we may never quite feel full enough.
Lastly, the digestive process requires time, because the gut must re-acidify itself to be able to process foods throughout the course of a meal. If you eat too fast, this function becomes compromised, which undermines the whole reason for eating—why eat if you can’t digest your meal?
So slow down, enjoy your food, and let your body do so as well.