Yes, you should chew well – here’s why

Yes, you should chew well - here's why
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Your mother was right: it is important to chew food well before swallowing it. Chewing is the first step in digesting the food we eat – it breaks food down into smaller particles, increasing the surface area so that digestive enzymes can more easily extract nutrients from it.

If we rush our meals, we don’t get the full phytochemical benefits of the foods we eat. Slowing down and chewing carefully allows us to absorb more nutrients, helps us maintain a healthy weight, and even provides dental health benefits.


The digestive process begins in your mouth as soon as you start chewing. When you break your food down into smaller particles, digestive enzymes can cover more surface area and begin to extract nutrients. For some foods, especially cruciferous vegetables and alliums, the breakdown of the food matrix structure results in chemical reactions that provide beneficial phytochemicals.

Phytochemical benefits of chewing well

The carotenoids in raw carrots are made more accessible when the cell walls of the plant are broken down by thorough chewing. Carotenoids are embedded in the food matrix and the structure must be broken down to allow the digestive system to extract and absorb them.1.2 For some foods, especially cruciferous vegetables and members of the onion and garlic family, the breakdown of the food matrix structure results in chemical reactions that produce beneficial phytochemicals.

Glucosinolates found in cruciferous vegetables (such as broccoli, cauliflower, kale, collard greens, and bok choy) are converted by the enzyme myrosinase into breakdown products, including indole-3-carbinol and isothiocyanates (ITC), which are compounds with beneficial anti-cancer activity.

The extent of ITC formation depends on a number of factors, such as the glucosinolate content of the food, temperature, pH, the presence of vitamin C (which accelerates ITC production) and , above all, the amount of food broken down by chopping. , crush or chew.

Glucosinolates and myrosinase are physically separated in the intact vegetable, and damage to the cellular structure is required to bring them into contact and initiate the chemical reaction. Heat inactivates myrosinase and also degrades vitamin C, which slows or stops the reaction. To maximize health benefits, cruciferous vegetables should be eaten raw or finely chopped before cooking.

Similarly, onions, garlic, leeks, scallions, and shallots contain an enzyme called alliinase which is damaged by heat and physically separated from the sulfur compounds it metabolizes. Physically disrupting the structure of plant cells by chopping or chewing them well triggers the chemical reaction that produces allicin and other beneficial compounds with antioxidant, anti-inflammatory and anti-cancer effects.3

Chewing thoroughly also improves the conversion of dietary nitrate to nitric oxide by oral bacteria. The body needs nitric oxide for a variety of functions, including cell signaling and blood pressure regulation. One of the two main sources of nitric oxide is dietary nitrate, which is converted to nitric oxide by oral bacteria on the surface of the tongue.

Green vegetables are the richest sources of nitrates and the production of nitric oxide by oral bacteria increases when we chew more carefully. Note that this process only occurs in the presence of oral bacteria.4-6 For example, when we blend cruciferous greens into a smoothie, we’ll get a good conversion of glucosinolates to ITC, but we won’t get as much nitric oxide production in the mouth as if we had chewed the greens in the mouth. place.


Dietary factors that affect the bioavailability of carotenoids
Garlic and onions: their anticancer properties
From nitrate to nitric oxide: the role of salivary glands and oral bacteria

Chew carefully and maintain weight

In addition to extracting more phytochemicals from vegetables, studies suggest that chewing carefully and eating more slowly helps maintain a healthy weight. Observational studies have shown that participants who reported eating slower had lower body weight or gained less weight over time, compared to faster eaters.7.8 In another study, a greater number of chews and a longer chewing time were associated with a lower body mass index.9

Chewing more carefully may promote a healthy weight by affecting signals of hunger and fullness, which could reduce calorie intake from the current meal and delay or reduce calorie intake from the next meal. A meta-analysis of chew time studies found that participants reported feeling lower levels of hunger after a meal that had a longer chew time than a shorter one.ten

Several studies have also shown that prolonged chewing reduces caloric intake either at that meal or at the next meal.10-12 For example, in one study, participants ate as much as they wanted from a meal while chewing 15 or 50 chews per bite, and those who chewed 50 times per bite consumed fewer calories.13 A similar study comparing 15 and 40 chews found similar results.14 A smaller bite size is also linked to lower food intake.15

Diet-induced thermogenesis, also known as the food thermic effect, is the energy burned to digest, absorb, and metabolize food. It is a significant contributor to our daily calorie expenditure, accounting for up to 10-15% of the calories we expend in a day.16 There is evidence that chewing more completely increases food-induced thermogenesis.16.17


Self-reported faster eating speed linked to higher body mass index in national survey of middle-aged women
Relationship between chewing behavior and body weight in fully dentate healthy adults
Effects of chewing on appetite, food intake and gut hormones: a systematic review and meta-analysis
Increasing the number of chews before swallowing reduces meal size in normal-weight, overweight, and obese adults
Chewing increases postprandial diet-induced thermogenesis

Better chewing protects our teeth

Chewing thoroughly stimulates more saliva production, which is a key factor in preventing tooth erosion and tooth decay (cavities). First, the extra saliva helps remove small food particles and sugars from the teeth.

Increased saliva production helps restore proper pH in the mouth after a meal by diluting and buffering acid – an acidic environment promotes erosion of tooth enamel. Additionally, saliva contains minerals, especially calcium and phosphate, which help remineralize teeth.18


Saliva and dental erosion

Take action

  • Chew food until it has a liquid consistency before swallowing it.
  • Take smaller bites and don’t overfill your fork or spoon.
  • Slow down by putting down your fork or spoon between bites.
  • Avoid distractions, such as watching television, during meals.

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The references:

  1. Lemmens L, Van Buggenhout S, Van Loey AM, Hendrickx ME. The reduction in particle size leading to cell wall rupture is more important for the bioaccessibility of beta-carotene from raw carrots compared to heat-treated carrots. J Agric Food Chem 2010, 58:12769-12776.
  2. van Het Hof KH, West CE, Weststrate JA, Hautvast JG. Dietary factors that affect the bioavailability of carotenoids. J Nutr 2000, 130:503-506.
  3. Nicastro HL, Ross SA, Milner JA. Garlic and onions: their anticancer properties. Cancer Prev Res (Phila) 2015, 8:181-189.
  4. Kobayashi J. Chewing well during meals may benefit health via the entero-liver nitrate-nitrite-nitric oxide pathway. J Gastroenterol Hepatol Res 2019, 8.
  5. Hezel MP, Weitzberg E. The oral microbiome and nitric oxide homeostasis. Oral Dis 2015, 21:7-16.
  6. Qu XM, Wu ZF, Pang BX, et al. From nitrate to nitric oxide: the role of salivary glands and oral bacteria. J Dent Res 2016, 95:1452-1456.
  7. Leong SL, Madden C, Gray A, et al. Self-reported faster eating speed is linked to higher body mass index in a national survey of middle-aged women. J Am Diet Assoc 2011, 111:1192-1197.
  8. Tanihara S, Imatoh T, Miyazaki M, et al. Retrospective longitudinal study of the relationship between weight change over 8 years and current eating speed. Appetite 2011, 57:179-183.
  9. Zhu Y, Hollis JH. Relationship between chewing behavior and body weight in fully dentate healthy adults. Int J Food Sci Nutr 2015, 66:135-139.
  10. Miquel-Kergoat S, Azais-Braesco V, Burton-Freeman B, Hetherington MM. Effects of chewing on appetite, food intake, and gut hormones: a systematic review and meta-analysis. Physiol Behav 2015, 151:88-96.
  11. Zhu Y, Hollis JH. Increasing the number of chews before swallowing reduces meal size in normal-weight, overweight, and obese adults. J Acad Nutr Diet 2014, 114:926-931.
  12. Higgs S, Jones A. Prolonged chewing at lunchtime decreases later snack consumption. Appetite 2013, 62:91-95.
  13. Borvornparadorn M, Sapampai V, Champakerdsap C, et al. Increased chewing reduces energy intake, but not postprandial glucose and insulin, in healthy-weight and overweight young adults. Nutr Diet 2019, 76:89-94.
  14. Li J, Zhang N, Hu L, et al. Improved chewing activity reduces energy intake in a meal and modulates plasma concentrations of gut hormones in obese and lean Chinese young men. Am J Clin Nutr 2011, 94:709-716.
  15. Zijlstra N, de Wijk RA, Mars M, et al. Effect of bite size and oral processing time of a semi-solid food on satiety. Am J Clin Nutr 2009, 90:269-275.
  16. Hamada Y, Kashima H, Hayashi N. Number of chews and duration of meals affect diet-induced thermogenesis and splanchnic circulation. Obesity (Silver Spring) 2014, 22:E62-69.
  17. Hamada Y, Hayashi N. Chewing increases postprandial diet-induced thermogenesis. Sci Rep 2021, 11:23714.
  18. Buzalaf MA, Hannas AR, Kato MT. Saliva and dental erosion. JAppl Oral Sci 2012, 20:493-502.

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