The surprising health impact of eating too fast

[Music] hello and welcome to Zoe shorts the bite-sized podcast where we discuss one topic around science and nutrition I'm Jonathan wolf and today I'm joined by Dr Sarah Berry and today's subject is eating rate which is really just a fancy way of saying how fast we eat our food so does that have any impact on our health indeed it does Jonathan and there's a lot more to eating right than just how it interacts with our weight quick let's get into it then or should I say slow [Music] tell us a bit more about eating rates Sarah I don't know about you Jonathan but these days it seems like it's easier to gobble down our food rather than mindfully take our time with a meal and this is probably because of the type of food that we're eating as well as the way we now live our lives definitely uh I think like half the time I'm now eating lunch while on a zoom call during the week or I'm sort of shoveling away some food while you know looking after the kids that sounds familiar for Missy many people 's lives are now and it's really not good for us essentially your brain needs time to realize it's full and Studies have shown that it takes between five or even up to 20 minutes for your mind to catch up with your belly and research also tells us that eating more slowly increases the response of appetite regulating hormones so these are hormones that tell us how full or how hungry we are and one study with children found that 42 of children whose parents reported that they ate quickly were also overweight and these children were also more likely to show overeating behaviors according to what their parents reported so in a nutshells Sarah you're saying eating faster makes it much easier for us to continue eating even when we're not actually hungry anymore I believe so and interestingly it seems that tendency to eat slowly might be something we inherit from our parents partly from rep applicating their habits and partly due to the food choices that we make based on what our parents brought us up to eat it makes sense that eating faster means taking in more energy and the research backs us up in our Zoe predict one study we saw that faster eaters ate on average 120 calories more per day than the slow eaters another child suggests that reducing or eating speed by around 20 can lead to reduction in energy intake of around 15 percent well that all sounds a bit magical and I have to say sorry that always makes me very suspicious now after like six years of Zoe So I if I eat more slowly will I really magically lose lots of weight okay so um there hasn't been loads of research on this and I think this is what makes it really exciting to be a nutrition researcher at a time where we're only just really unraveling all of the evidence but what has been shown is that there is a link between eating rate and there is a link between the risk of developing obesity so for example research from Singapore published in 2020 suggested that people who self-report a fast eating raid carried on average five kilograms more body weight than slow eaters and they ate also on average an extra 105 calories per day the researchers also found that the fast eaters had a larger waist circumference by about three centimeters which we know is really important in terms of our metabolic health and fast eaters were also more likely to develop overweight and particularly abdominal weight so this is the way particularly around your belly which is linked to having more visceral fat which is a type of fat that sits in inside your abdominal walls and surrounds all of your organs now this study wasn't a one-off though Jonathan and there has actually been lots of other studies that have shown an association between how quickly you eat and excess body weight well that is interesting and I would say surprising um I'm assuming that that then has plenty of knock-on effects for our overall health if so can you sort of take us through what that means for these different areas area is your cardio metabolic health so that's you know heart and blood vessels and also things like stripes and things like that right Sarah yeah that's correct correct and in 2017 a cardiologist from Hiroshima University in Japan studied more than a thousand people over five years to figure out the relationship between eating rate and something called metabolic syndrome and I looked this up and metabolic syndrome is the the name that researchers now like to use for five risk factors for things like heart disease and diabetes and stroke which are obviously very serious and those risk factors are apparently high blood pressure high triglycerides which I think we often call sort of blood fat high blood sugar low levels of good cholesterol and finally a a large waistline compared to average that's correct and what found was that the twice as likely to develop this metabolic syndrome and a high heating speed correlated with greater weight gain correlated with higher blood sugar higher levels of LDL cholesterol which is our bad cholesterol and also a larger waistline and interestingly Jonathan a lot of these associations remained even after we accounted for changes in body weight so even after we accounted for changes in body weight we still found that fast eaters had higher blood sugar and higher levels of bad cholesterol and so Sarah it sounds like this is similar to what we found with our own Zoe predict study where you were saying that eating rate is associated with energy into a body weight and this sort of cardio metabolic risk in that study which was UK and U.S yeah that's correct and there's been other research that's been published as well that has drawn a link between eating faster and higher risk also type 2 diabetes and Studies have shown that this may be because chewing more slowly stimulates more insulin release which means better glucose control and we think that this might be because if you chew for longer you have more saliva uptake and this causes an earlier insulin and glucose release and what about digestive issues Sarah we do know that actually fast eaters do often report poor digestion and a study has shown that they may also get more acid reflux than slow eaters so the overall message seems pretty clear sort of slow down you know at the kitchen table Yeah I think the evidence shows Jonathan and that it is going to be helpful on an individual basis and there's lots of research exploring if this could be a good health and weight loss strategy for the population as a whole now Sarah pretty much everything you've described so far are really Association studies so they show people who put on weight were eating faster but they don't prove the two are linked so in other words you know if one of those fast eaters switched to slow eating it might not change anything right and the gold standard I you know I know in nutritional science because you uh talk about this all the time as a randomized controlled trial to really prove that it's the eating speed that causes this um rather than everything else and I know from many conversations with you and Tim and many others that often there are these effects that are found in these sort of observational studies like this where you study people over time and then when you do a randomized control trial and you say let's actually make people change their behavior you know often that disappears because maybe there's some compensating effects that the two they would just happen to be linked you know like you know if people aren't well then they're not able to do lots of exercise so you see a much bigger impact of people who are doing exercise because you've already sort of removed all the people who were who were sick where are we on this in terms of eating rates yeah so I think you're right Jonathan in saying a lot of the evidence is this Association evidence but what that does is it does give us this researchers that kind of first clue that something interesting is going on and there have been a small number of these Interventional studies particularly ones that point to interesting mechanisms so for example Even in our own Zoe data we do see that if we look at fast eaters and slow eaters those that are eating their meals fast do have a higher glucose response compared to those that are eating their meals slow and this is immediate real-time data that we're collecting we also know from a study that was conducted in 50 14 teenagers those who slowed down their eating rate which was by waiting 30 seconds between each bite which I think is quite hard to do they lost a significant amount of weight after one year and I think this is what would be really interesting to explore and I really hope we can explore this in our Zoe predict data so in addition to this study with teenagers another example of a study that found that when female volunteers slowed down their eating speed they ate on average 60 fewer calories per meal now interestingly they also felt more full when than the people who are eating faster who ate more calories that is really interesting so how do we change our eating rate in practice I mean is it as simple as saying sort of two more slowly or do I need to wait 30 seconds between each bite so I think I think the ways too so firstly a study from China found that people cut their calorie intake by over 10 if they chewed their food 40 times instead of uh 15 times um and this is because it had double the benefit of allowing those appetite regulating hormones that tell us how hungry we are or how full we are to kick in and the saliva will begin to to this whole digestive process for you but this can be quite tricky I think to to chew 40 times every mouthful so another tactic that I think might be a little bit more achievable for everyone is just to put your Cutlery down between each mouthful of food so I don't know about you Jonathan but if I'm having a sociable meal or I'm out with friends deep in conversation then I eat a lot more slowly because I'm putting my Cutlery down taking part in that conversation and slowing down naturally the rate I'm eating that way so I have to say the idea of on top of that like putting my Cutlery down between each mouthful food seems a bit crazy um so I do prefer some of the other tips that we found in our research so one of them I thought which made a lot of sense to me is you might want to try not eating in front of screens when you're a lot more likely to be eating mindlessly and quickly and sort of shoveling it in and not thinking about it um drink water during the meal so that sort of that's a way to interrupt right versus somebody who's just not drinking anything um take smaller uh bites and don't wait until you're completely famished to eat which I thought was interesting because if you're completely famished then you are sort of really um shuffling this in and the idea that you're you know you're doing good by waiting you know might actually be balanced out um so what about I mean all of this leads me to think about the texture of food um and I'm sort of assuming that this can play a big role and I think that naturally makes me start to think about how the texture of food is so transformed with today's sort of ultra process food is there any science on this so I think that the texture is really important when we consider the health effects of foods and I think it's really important to consider now given that over the last 50 years or so the texture of much of our food has changed with all of the new processing techniques and it's not something I think we give enough attention to and interestingly there was a recent study that was only published last year that looked at the relationship between eating raid and food texture as well as the level of processing of the food now it has been argued by some people that part of the reason that heavily processed food is linked with weight gain is because it's really energy dense so it's in a small package packed full of calories so therefore we eat more calories in a short period of time now I'm quite skeptical whether this is the main reason why heavily processed food is bad for us because I think there's other possibilities and really interestingly this study found that hard minimally processed so unprocessed food and also hard heavily processed food food was consumed slower overall okay so the hard food whether it was processed or unprocessed was consumed slower overall compared to soft food so hard minimally processed foods in this case were classified as rice which you might find hard to believe Jonathan is classified as Hardware yes you've got to be a nutritional side of something that rice is a hard food but okay keep going okay uh well let me tell you what soft food is in a minute and then we'll see um uh fresh crunchy veg was also classified um as hard as well now um hard uh heavily processed food included like fries vegetable crisps or chips um now what was interesting more calories were consumed when people ate the soft food and this was regardless of whether it was minimally processed or heavily processed soft food and by soft food we mean things like instant mashed potato fish bites and fruit yogurt God it says like practically a liquid um is the ultra process that's interesting because I was just thinking about the difference between going and eating a meal from McDonald's and eating something that was more like uh a whole food in the way that our ancestors you know any meal would have been until 100 years ago right where it would have been lots of plants and which are like beans and lentils and you know sweeps any of these things which are actually relatively crunchy they're fibrous you know it's gonna take quite a long time to chew and bite and so I thought you were going to push us towards this thing that these foods that we eat seem incredibly soft and I think it's related to having sort of no fiber in them um and it sounds like actually in this study you're not even that far you're even just saying within ranges of things which are already quite processed that you're seeing this difference yeah and I think what was interesting there was like this graded response with um unprocessed hard food being a associated with the slowest rate of eating processed hard food the next lowest then unprocessed soft food getting faster and then highly processed soft food the fastest amazing so it's not all to do with processing that's also the texture of the food so Sarah you've sort of given us this Whistle Stop tour of this new area of scientific research what's your verdict so my verdict is that this is a this is a really exciting area of research that I'd love to explore further and I think whilst there is an Interventional evidence to show definitively that people who eat fast if they slow down the rate that they're eating you know improve their weight improve other health measures I think that the evidence is interesting enough to suggest that we should look into it further and I think it also really highlights an important area that we often talk about Jonathan about how we should think not just about the food that we're eating but the way in which we're eating it which we call our dietary habits so we've talked before about the importance of thinking of the time of day that we're eating about fasting so our eating windows for example and I know that we often talk about intermittent fasting so you know eating in a shorter period of time and this is just one of those other factors that I think is really interesting that we might want to consider when we think about our eating habits I think it's really interesting that it seems to have come through so clearly in the data and like in our own Zoe data as well as as elsewhere and um I'm also struck that we can easily become quite divorced from our own sort of body signals about are we hungry are we not hungry um and that there's a lot of really clever nutritional scientists who could be building food products that sort of trick us past these points you know that make thing you know they're things that are just so hyper palatable which again it's in the same area right of sort of getting us to do things we we don't want and it wouldn't surprise me if we dig more into this that you see that you know speed of eating is also related to the sort of foods that you're eating because I think we all know that it's really easy to eat an ice cream really fast and to keep eating it right because it's just so nice and um I quite like nuts but I'm never in a point where I've just got to finish the nut ball so there's definitely some linkages here I guess which is interesting and so I I'm you know I think it'd be really interested to do the studies and I think what we tend to see right in this is there's it's very unlikely to be any Magic Bullet and there's a lot of interrelationship here so I guess also you know the other thing I'm struck by is we haven't talked a lot about fiber but it seems like you know if you're eating foods that are higher in fiber we know they're incredibly good for your long-term uh Health you know can mean that you might live years longer and I could see that um the sort of foods that are higher in fiber are generally you know not hyperpalatable like Ultra processed foods you probably have to chew them a bit more so you can see how these things might work together or in the opposite direction right you're going to somewhere selling you fast food you know you don't need to chew any of this and um and therefore you can be sort of in the it sort of feels like you're you're either in a good place or you could potentially be in a doubly bad place where the food isn't very good for you and you're going to find it easy to sort of eat it very fast and um and over it yeah and I think we we know that fiber-rich Foods tend to be not fair energy dense so if you were to have two equal weight foods but one had a lot of five in it you'd have to actually consume probably three or four times as much of that food to get the same amount of energy as you would from a balanced weight meal that had little fiber in it I think as well Jonathan do you know what's really fascinating thinking about eating rate the speed in which we're eating is thinking about how we're eating now and I'd be really interested to know where the people's eating rate has changed pre versus post-covered in terms of how many people now are working at home are doing exactly what you said earlier that you do which is you wolf down your food even between a zoom meeting or on a zoom meeting yet typically when we were in physically in an office environment I think we would block time off because we knew that we had to either go and physically get food or or you know we would be less or more self-conscious about eating it I think in front of people during a meeting so I do wonder whether that's changed that'd be really interesting to look at well if if you've enjoyed today's podcast and you'd like to try Zoe's personalized nutrition program to improve your health and manage your weight you can get 10 sent off by going to join zoe.com podcast I'm Jonathan wolf and I'm Sarah Berry join us next week for another Zoe podcast [Music] foreign [Music]

Channel: ZOE

Views: 112,141

Keywords:

Id: w3bRcfY9Kxc

Length: 20min 32sec (1232 seconds)

Published: Mon May 22 2023