Could chewing your food help you lose weight?

The Importance of chewing

Many of us have been told to “chew your food properly” as children, but with so many of us eating on the go, whilst watching the tv or even in front of the computer at work do we really chew our food properly? Does it even matter? The answer is that yes it does matter, and it may well unlock a technique to help us lose weight.

Chewing is not just about cutting the food in to smaller pieces. The role of this first phase of digestion is to mix the food with saliva. Our saliva contains enzymes that also work to break down food. Skipping this phase will result in larger boluses of food entering our stomach, making it harder for the stomach to do its work properly and leading to digestion problems down the line.

Ultra-processed foods such as ready-meals and food from fast food restaurants are much softer than what our ancestors would have been used to, meaning that the art of chewing properly is becoming extinct; there simply isn’t a need.

Chewing affects the rate of eating

There are plenty of studies that show that eating fast is associated with weight gain. (1,2) We even know that the quicker we eat the more we are likely to weigh. And the more we weigh the higher the risk of Type 2 Diabetes (3).

In contrast there is plenty of scientific research showing that you eat less volume of food/ calories when you slow down the rate of eating. One of the most effective ways to slow down the rate of eating is by chewing food more thoroughly.

One trial looked at chew rates of participants eating pizza and found that those that chewed at 1.5x their baseline rate reduced their food intake by 9.5%, whilst those that chewed at twice their usual amount reduced their food intake by 14.8% (5)

Allowing the hormones to work

Eating more slowly means that you are more in tune with your physiology. There are multiple ways in which your brain detects fullness. One is by the stretch receptors in the stomach signalling volume of food. The other is by the release of hormones in your gut. Although effective, these hormonal signals work much slower. They can take up to 20 minutes to start working. Many of us may well have consumed our main meal and pudding in that time. 

One study asked volunteers to eat an ice cream over 5 min period and then a 30 min time period. The group that were asked to eat more slowly reported they felt fuller, and there was indeed a higher level of satiety hormones (the hormones that signal to your brain that you’re full.) (4)

Allowing your hormones the time to feedback to your brain regarding fullness levels may also decrease the amounts of snacks you crave later on. Volunteers of normal weight that were asked to participate in a study were allocated to one of two groups. The first group

were asked to eat a meal within 6 minutes and the other within 24 minutes. The group eating over 24 minutes reported greater enjoyment of the meal and felt fuller 2 hrs later. Three hours later they were offered a snack and the slower rate eaters consumed 25% less energy from this snack. (6)

Tips to slow down

• Ensure you don’t overload your fork.
• Chew your food. Notice how long you normally chew for – either the number of times, or how long in seconds. Start to increase this until you do 20-30 chews/ 20seconds per mouthful
• Put your knife and fork down after each mouthful
• Allow more time to eat a meal and sit on a chair by a table (eg allocate 30 minutes)
• Avoid extreme hunger. This will increase the chances that you may want to eat faster
• Eat foods that need chewing; meat and vegetables in particular provide more nourishment for your gut

Other Benefits

• Improving digestive health; people may find less bloating and abdominal cramps, symptoms typically associated with IBS
• Better absorption of nutrients
• Increased enjoyment of meals
• Reduced level of stress
• May mean you eat with others and social eating has long been shown to improve mental health
• Mindful eating is where you pay more attention to the food you’re eating; this would include taking notice of the smell, feel, texture and what it looks and tastes like. It is about being aware of the 5 senses as you eat.

References

(1) 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.

(2) Leong SL, Madden C, Gray A, Waters D, Horwath C. Faster self-reported speed of eating is related to higher body mass index in a nationwide survey of middle-aged women. J Am Diet Assoc. 2011 Aug;111(8):1192-7. doi: 10.1016/j.jada.2011.05.012. PMID: 21802566.

(3) Takayama S, Akamine Y, Okabe T, Koya Y, Haraguchi M, Miyata Y, Sakai T, Sakura H, Sasaki T. Rate of eating and body weight in patients with type 2 diabetes or hyperlipidaemia. J Int Med Res. 2002 Jul-Aug;30(4):442-4. doi: 10.1177/147323000203000413. PMID: 12235929.

(4) 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.

(5) 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 Jun;114(6):926-931. doi: 10.1016/j.jand.2013.08.020. Epub 2013 Nov 9. PMID: 24215801.

(6) Hawton K, Ferriday D et al. Slow Down: Behavioural and physiological effects of reducing eating rates. Nutrients. 2018;11 (1):50 doi:10.3390/nu11010050