Could eating quickly lead to weight gain?

Several studies have found that the speed at which we eat may make a difference in our weight. People who eat faster tend to gain way more than those who eat more slowly.

In one study, people who ate more quickly had twice the odds of being overweight than those that ate slowly. If they also ate until full with every meal, they had triple the risk of being overweight! [1] In a separate publication, when analyzing the results of 23 studies, researchers found that people who ate quickly had twice the risk of being obese. [2] Another study found that people who eat quickly tend to be heavier and gain more weight over time (in this case over 8 years), compared with slower eaters. [3]

Studies have also shown that people who eat more slowly tend to consume fewer calories. In one study, people were told to eat at different paces. People in the slower-paced group ate fewer calories than the group eating at a normal pace. [4]

This may be because eating slowly increases the levels of gut hormones that cause a sense of fullness, leading to less calorie consumption. Peptide YY and glucagon-like peptide-1 (GLP-1), both fullness hormones have been found to be higher after a slow meal than after a fast meal. [5] This is an especially intriguing finding because many of the most successful weight loss medications increase our GLP-1 levels. So eating more slowly is just a natural way to do this.

Other studies did not find the same result. In one study, eating speed at breakfast did not affect fullness hormone levels. However, the desire to eat was lower 60 minutes after the meal was lower in the slow versus fast eating group. [6a]

It appears that chewing is one of the keys to this process. In an interesting study, people were divided up into two groups - those that were told to chew each bite more and those that were told to pause in between bites so that the overall time to eat a meal was the same as with the people who were chewing more. Two hours later, people in the group who chewed for longer ate fewer candies than people who chewed at their regular rate. Interestingly snack intake was the same in the group who chewed at their normal rate but paused between bites and the group that chewed normally but did not pause. [6]

Another study found that the number of chews and the duration of chewing are negatively correlated with weight whereas chewing speed is not. [7]

Bottom line? It appears that eating more slowly and chewing slowly may help keep our weight down. And this may be because we are giving our bodies the time to send signals (in the form of hormones) to our brain to tell us that we are full.

1 - Maruyama K, Sato S, Ohira T, Maeda K, Noda H, Kubota Y, Nishimura S, Kitamura A, Kiyama M, Okada T, Imano H, Nakamura M, Ishikawa Y, Kurokawa M, Sasaki S, Iso H. The joint impact on being overweight of self reported behaviours of eating quickly and eating until full: cross sectional survey. BMJ. 2008 Oct 21;337:a2002. doi: 10.1136/bmj.a2002. PMID: 18940848; PMCID: PMC2572205.

2 - Ohkuma T, Hirakawa Y, Nakamura U, Kiyohara Y, Kitazono T, Ninomiya T. Association between eating rate and obesity: a systematic review and meta-analysis. Int J Obes (Lond). 2015 Nov;39(11):1589-96. doi: 10.1038/ijo.2015.96. Epub 2015 May 25. PMID: 26100137.

3- Tanihara S, Imatoh T, Miyazaki M, Babazono A, Momose Y, Baba M, Uryu Y, Une H. Retrospective longitudinal study on the relationship between 8-year weight change and current eating speed. Appetite. 2011 Aug;57(1):179-83. doi: 10.1016/j.appet.2011.04.017. Epub 2011 May 4. PMID: 21565235.

4 - Shah M, Copeland J, Dart L, Adams-Huet B, James A, Rhea D. Slower eating speed lowers energy intake in normal-weight but not overweight/obese subjects. J Acad Nutr Diet. 2014 Mar;114(3):393-402. doi: 10.1016/j.jand.2013.11.002. Epub 2013 Dec 30. PMID: 24388483.

5 - Kokkinos A, le Roux CW, Alexiadou K, Tentolouris N, Vincent RP, Kyriaki D, Perrea D, Ghatei MA, Bloom SR, Katsilambros N. Eating slowly increases the postprandial response of the anorexigenic gut hormones, peptide YY and glucagon-like peptide-1. J Clin Endocrinol Metab. 2010 Jan;95(1):333-7. doi: 10.1210/jc.2009-1018. Epub 2009 Oct 29. PMID: 19875483.

6a - Shah M, Crisp K, Adams-Huet B, Dart L, Bouza B, Franklin B, Phillips M. The effect of eating speed at breakfast on appetite hormone responses and daily food consumption. J Investig Med. 2015 Jan;63(1):22-8. doi: 10.1097/JIM.0000000000000119. PMID: 25361054.

6 - Higgs S, Jones A. Prolonged chewing at lunch decreases later snack intake. Appetite. 2013 Mar;62:91-5. doi: 10.1016/j.appet.2012.11.019. Epub 2012 Nov 30. Erratum in: Appetite. 2017 Sep 1;116:616. PMID: 23207188.

7 - Zhu Y, Hollis JH. Relationship between chewing behavior and body weight status in fully dentate healthy adults. Int J Food Sci Nutr. 2015 Mar;66(2):135-9. doi: 10.3109/09637486.2014.979317. Epub 2015 Jan 13. PMID: 25582174.