Search Results for "chewing"
The answer is yes, but before anyone gets too excited, the range of extra calories burnt with 15 mins of chewing is about 6-11 kcal. These are the findings from a rather interesting study by Yuka Hamada and colleagues from Tokyo, published in OBESITY, which actually studied the effect of fast vs. slow chewing (with or without 15 mins of gum chewing after the meal) on substrate utilization, splanchnic blood flow and diet-induced thermogenesis. The 12 healthy normal-weight males, on four different days, were asked to chew a 621-kcal test meal for as long as possible as many times as possible in the slow-eating trials, while they consumed the same meal as rapidly as possible in the rapid-eating trials. In the gum–chewing trials, the subjects chewed a 3-kcal gum for 15 min after the meal. In the non-gum–chewing trials, they consumed 3 kcal of sugar with the test meal instead of chewing the gum. With both slow eating (~650 chews) and fast eating (~235 chews), gum chewing added about 850 chews to the eating episode. In both cases, the additional chewing of gum added about 6-11 extra calories to post-prondial thermogenesis (largely due to increased protein oxidation), an effect that lasted about 45 minutes after the meal (so well into after the actual chewing). Gum chewing did not change splanchnic blood flow. As the authors note, the gum chewing increased post-prandial thermogenesis in the fast meal but this increase was not greater than the additional calories burnt from chewing with the slow meal. Thus, while you would actually burn the most extra calories by eating as slow while chewing each bite as often as possible, this may be hard to do in real life (chewing habits are notoriously difficult to change). You’re second best bet would be to add 15 mins of gum chewing after the meal, especially when you inhaled our food. Will this help you lose weight? Probably not – but a few extra calories burnt everyday may well ward off weight gain (although just how much, is anyone’s guess). If you have any experience with how gum chewing has affected your eating behaviour, I’d love to hear about it. @DrSharma Edmonton, AB
Last night, at my virtually “sold out” public show in Thunder Bay, Ontario, I emphasized the importance of eating slowly and chewing every bite. But does this really help reduce overeating? This question is addressed in a randomised controlled cross-over study by Yong Zhu and James Hollis from the University of Iowa published in the Journal of the Academy of Nutrition and Dietetics. The study was conducted in fourty-five 18- to 45-year-old normal-weight, overweight, and obese participants, who were asked to attend three test sessions to eat pizza for lunch until comfortably full by chewing each portion of food either 100%, 150%, or 200% of their baseline number of chews before swallowing. Food intake in the sessions with 150% and 200% of their baseline number of chews was reduced significantly, by 9.5% and 14.8%, respectively, compared with the 100% session. As one might expect, increasing the number of chews also prolonged meal duration and reduced eating rate while subjective appetite at meal termination or during the immediate postprandial period did not differ. These data are certainly compatible with the hypothesis that increasing the number of chews per bite might reduce food intake and may thus assist in body-weight management. Obviously, whether not increased chewing of each bite will actually assist in sustainable weight loss is another question – in fact, one that still needs to be answered. Nevertheless, eating slowly while chewing and savouring every bite certainly seems a promising strategy to reduce overeating and feel full with less. If you have experimented with chewing more to better manage your weight, I’d like to hear about it. @DrSharma Thunder Bay, ON Zhu Y, & Hollis JH (2013). Increasing the Number of Chews before Swallowing Reduces Meal Size in Normal-Weight, Overweight, and Obese Adults. Journal of the Academy of Nutrition and Dietetics PMID: 24215801 .
There are people who claim that chewing gum helps them control their appetite but does this really work? James Shikany and colleagues from the University of Alabama have addressed this question in a randomised controlled trial published in OBESITY. In this 8-week study, 201 overweight and obese adults were randomised to receiving either printed material on good nutrition and chewing gum for a minimum of 90 min/day or to only receiving the printed nutrition information only. At the end of 8 weeks, there was no signficant change in body weight (although waist circumference decreased by about 1.5 cms) in the intervention group. There was a small drop in blood pressure (-3 mmHg) in the gum chewers but this fall was not statistically significant from any changes in the control group. Thus, the authors conclude that chewing gum on a regular schedule for 8 weeks did not facilitate weight loss in these overweight and obese adults. So much for this RCT – if you have personal experience with gum chewing and what it does to your hunger or appetite, I’d sure love to hear about it. AMS Edmonton, Alberta photo credit: canonsnapper via photopin cc Shikany JM, Thomas AS, McCubrey RO, Beasley TM, & Allison DB (2012). Randomized controlled trial of chewing gum for weight loss. Obesity (Silver Spring, Md.), 20 (3), 547-52 PMID: 22076595 .
Yesterday, I had my remaining wisdom teeth extracted. As anyone, who has had this done to them knows, chewing with a swollen cheek and a gaping wound is no fun. Interestingly, chewing also appears to be impaired in folks with severe obesity (even without the trauma of wisdom tooth extraction). This, at least, was the finding from a study by Jean-Luc Veyrune and colleagues (faculté d’Odontologie, Clermont-Ferrand, France) published in the latest issue of Obesity Surgery. Veyrune compared the chewing parameters in a group of 44 obese adult patients (BMI = 49.1 +/- 7.2) scheduled for gastric bypass surgery with those of a control group (BMI=20.9 +/- 2.1). In both groups, the subjects’ dental status was characterized by the number of functional dental units. Kinematic parameters, namely chewing time (CT), number of chewing cycles (CC), and chewing frequency (CF), were video recorded during the mastication of five natural standardized foods (banana, apple, sweet jelly, peanut, and carrot). The particle size distribution of the expectorated bolus from carrot and peanuts was characterized by the 50th percentile (D (50)) (sounds kind of yucky to me). Even in fully dentate obese patients, chewing time and chewing cycles were higher with lower values for D (50). This was particularly true for carrot and peanut (that obviously require more chewing than banana, apple or jelly). As restrictive bariatric surgeries (like adjustable gastric banding), require fine mastication of foods, this study is again a reminder to evaluate both dental status and chewing ability in patients scheduled for bariatric surgery. Obviously, the ability to properly chew healthy foods (which generally require a lot of chewing – try biting into an apple with lose teeth) is a prerequisite for health eating. Dental assessments can be an important barrier to healthy eating and should be part of the general assessment in bariatric patients. AMS Edmonton, Alberta
Every now and then, a landmark study comes along that definitively answers an important question, and, perhaps more importantly, lays to rest many of the theories that float around both in the scientific literature and the lay media. It would perhaps not be superlative to note that just such a study by Kevin Hall and colleagues (presented just a few weeks ago at the 6th Biennial Canadian Obesity Summit) has now been published in Cell Metabolism. The study examines what happens to calorie intake and body weight when people have free access to a diet largely composed of ultra-processed foods vs. a diet composed of unprocessed foods. Ultra-processed foods have been described as “formulations mostly of cheap industrial sources of dietary energy and nutrients plus additives, using a series of processes” and containing minimal whole foods. Importantly, the two diets were carefully matched for presented calories, energy density, macronutrients, sugar, sodium, and fiber. Although protein, carbohydrate, and fat content were virtually identical, the ultra-processed foods differed substantially from the un-processed foods in the proportion of added to total sugar (∼54% versus 1%, respectively), insoluble to total fiber (∼77% versus 16%, respectively), saturated to total fat (∼34% versus 19%), and the ratio of omega-6 to omega-3 fatty acids (∼11:1 versus 5:1). The 20 weight stable healthy participants, who spent over four weeks in an in-patient metabolic ward, were instructed to consume as much or as little of the foods offered with one diet over a two week period before switching to two weeks of the other diet (in a random cross-over fashion). In short, during the 2nd week of eating the ultra-processed diet, subjects consumed about 500 kcal more per day than during the 2nd week of the unprocessed diet. This was accompanied by an almost 2 lb weight gain on the ultra-processed diet (whereas weight reduced by about the same measure on the unprocessed diet). This response was seen irrespective of which diet came first or of the baseline BMI of participants. To set this study in perspective, there have long been theories about how the increased availability of ultra-processed foods may be playing a causal role in the obesity epidemic. Thus, as the authors point out, “Ultra-processed foods may facilitate overeating and the development of obesity because they are typically high in calories, salt, sugar, and fat and have been suggested to be engineered to have supernormal appetitive properties that… Read More »