 Today I want to talk about something that probably everyone in this room has experienced at one point or another and that is food cravings. This is a topic that I think is really important because it has such a profound impact on our eating behavior and ultimately our waistlines and our health. I also think it's a really good illustration of how we can bring together modern neuroscience with an evolutionary perspective to gain insights into ourselves insights into how we tick. Here's what we're going to talk about today. First I'm going to define what a craving is then I'm going to talk about how cravings arise what's the mechanism then I'm going to talk about which foods trigger cravings the most so sort of a brief literature review on that and then I'm going to give you some broad principles on how to manage cravings. So what is a craving? I'm going to show you a series of images in two groups five images per group and I want you to pay close attention to how you feel as you're looking at these images so really pay attention to how you feel as you see these images. First group finish boiled potatoes cucumbers apple broccoli that's the first set of images now I'm going to show you a second set of images and again pay attention to how you feel as you're looking at these hamburger and fries brownies chocolate pastries chips so did you notice anything different when you were looking at these two sets of images it felt different to look at them didn't it if you're like most people you probably didn't feel much when you're looking at the first set of images but as you were looking at the second set you may have felt a feeling of desire welling up inside of you at least certain of those images you may have felt you may have salivated a little bit you may have felt a little hunger pang developing and this is the experience of a craving but how exactly do we define that term craving is a state of heightened eating motivation that is directed at a specific food so it's not the same as hunger which is a nonspecific motivation toward calorie-containing food in general so it's a motivational state toward a specific food and there's another thing I want to explain about cravings that I think is really important and that's that we don't control cravings cravings are something that arise from the non-conscious brain and that we experience but that we're not in control over we're not in control of so we can control our behavior in response to cravings but we can't control when or how we experience that state though how does this happen what's the mechanism well to begin to answer this question and since this is the ancestral health symposium I'm gonna take an evolutionary perspective on this so let's say you're an engineer by the name of Nat RL selection and you're trying to design an organism that's able to survive and thrive on the African savanna you know a few things to start off with you know that energy is critical for survival and reproduction so your organism is going to have to be efficient at obtaining energy second you know that the primary forms of available energy are carbohydrate fat and protein if you're an animal and not a plant but you have to design your organism to have an intrinsic hard-wired motivation to seek and consume carbohydrate fat and protein to fuel itself but it's not always obvious on the surface which foods contain carbohydrate fat and protein so you also have to wire your organism to be able to learn through experience which foods supply those substances and furthermore your organism has to be able to tune its motivational level to match the value of the item so it's worthwhile perhaps to hunt an antelope for three days but it's not worthwhile to go on a foraging expedition for three days for a handful of berries so the organism has to be able to match the motivational level to the value of the food item and what I'm going to show you in this talk is that roughly speaking this is how humans are wired this is how it works when we eat food that food enters our digestive tract goes into the stomach and then to the small intestine and the small intestine contains receptors for a great number of things in our food but the ones that we're interested in today are sugar starch fat protein salt and glutamate so these receptors are specifically detecting sugar starch fat protein salt glutamate in fact detecting starch indirectly by the glucose that's that's generated during digestion glutamate is that meaty umami flavor that's in bone broth and soy sauce and monosodium glutamate and once it detects those things it sends a signal to the brain that informs the brain of what you've just eaten so it tells the brain what you've eaten and what the concentration is of those different substances in your food what happens once it gets there we we don't actually know how that signal gets to the brain yet we do know once it gets to the brain it activates a brain region called the ventral tegmental area this is one of the key dopamine producing areas of the brain this is really the the primary area that produces the dopamine that motivates us and that causes our cravings so the ventral tegmental area once it starts producing dopamine that dopamine goes primarily to a region called the ventral striatum also known as the nucleus accumbens and the ventral striatum is really intimately involved in generating motivational states basic motivational states and cravings which are a type of motivational state so whether it's sex or drugs or gambling or food or whatever the motivational state is whatever the craving is the ventral striatum is going to be involved in that so dopamine starts to spike in the ventral striatum and the more concentrated those nutrients are that we saw in the last slide the higher the level of dopamine you're going to get in your ventral striatum and the more pronounced the motivational state so this is just another way of showing the same thing we have the ventral striatum illustrated on the brain and then below we just have a synapse with some dopamine coming out of it so what happens when that when that dopamine starts to spike in your ventral striatum well it does a couple of things the first thing it does is it creates a motivational state creates and accentuates the motivational state to keep doing the thing that you're doing as the dopamine spiking so if you're eating that pizza you're gonna be really into eating more of that pizza and perhaps having another slice or three but the second thing it does is even more important it causes you to learn and to explain how this happens I'm gonna go back to a key experiment that many of you are probably familiar with that was performed by Ivan Pavlov and dogs so dogs when they see a food especially a food they really really like they start to salivate and they get really excited right so food activates a motivational and a digestive preparatory state in dogs that causes them that motivates them to obtain and eat the food and prepares their body for digesting it however if you ring a bell around a dog it doesn't really mean anything to it that's a meaningless sensory stimulus so what Pavlov did was he showed that if he consistently rang a bell at the same time as he fed the dogs he did this over and over again so the dogs came to associate the sound of the bell with the food and that bell became a reliable predictor of the food after that training he could ring the bell by itself and it would activate that same excitement and that same salvation that he saw toward food initially so the dogs learned that this sensory stimulus predicted food and it activated a motivational and digestive state and this is basically how it works in humans as well so when that dopamine starts to spike your brain starts to really pay attention to what's going on in your surroundings it notes very carefully and this is all on a non-conscious level it notes the smells that are happening the tastes that are happening the texture of the food it notes the appearance of the food triangular shape of the slices and the round pepperonis in the box it came out of it notes the location where you ate it who you were with what the situation was and those sensory stimuli become motivational triggers the next time you experience them so just like Pavlov's dogs learn to be motivated by the ringing of the bell which initially was a meaningless sensory stimulus we learn to become motivated by the sensory stimuli that are associated with the foods that we're eating and so the next time you smell that smell the next time you go to a place where you've eaten pizza before etc it gets your dopamine spiking again and it activates that motivational state in other words it causes a craving and so the more concentrated are these nutrients here in your food the higher your dopamine is going to go and the more it's going to drive this eating reinforcement craving cycle and this is really I think a major driver of our eating behavior or at least of many people's eating behavior in the modern world but one thing I want to emphasize about this that I think is really important is that this happens for all foods not just junk foods this happens for apples this happens for salmon this happens for collard greens with you know salt and oil this happens for everything but certain foods by virtue of their physical and chemical properties drive this cycle more than others and a lot of our modern foods basically drive it too hard and motivate us too much to to eat them and that can drive consumption of unhealthy food and over consumption of food so this system is not broken in the modern world it's doing exactly what it was designed to do the problem is we're giving the system the wrong cues through the foods that we're eating which are too calorie dense too refined and too hyper palatable and as well as having a food environment that's constantly feeding the system cues that are spiking our dopamine and spiking our motivation food cues like images of food on TV smells of food as you're walking down the street etc. All right so now I want to show you a little bit about how this works in real life as I was doing the research for my book I had the good fortune of being able to participate in an FMRI experiment so this is functional MRI basically it's a non-invasive way of looking inside your brain and seeing what parts of your brain are being activated and so I'm laying in this FMRI machine with a an inflatable cap around my head to really hold my head still and I'm looking at images of food on a screen so I'm perceiving sensory stimuli that are reminding my brain of food on a screen and there's three different types of images I'm looking at I'm looking at and they're all mixed together randomly I'm looking at images of calorie dense highly palatable foods things like pastries pizza potato chips I'm looking at low calorie healthy foods like strawberries celery and apples and I'm also looking at non-food items like shoes and cars and basically we're using those because there's a certain brain activity that happens when you're just looking at images in general and so you can use that data to kind of divide out all the noise that's happening when you're just looking at something and specifically look at the brain activity that's happening when you're looking at food and so here's an image of what was going on in my brain when I was looking at the junk food and this is illustrating my brain at the level of the ventral tegmental area again this is a part of your brain that makes that dopamine that's really involved in motivating you to eat food there's another thing I want to mention about this before we proceed and that is that I skipped two meals and rode my bike to the medical center for this experiment so I I wanted to put my brain in a really in an energy depleted state so that it would respond especially strongly to food and so as you can see in this image where the arrow is pointing that's my ventral tegmental area if you look at the scale bar on the top you can see that my VTA is is quite strongly activated as well as some associated regions in the in the forebrain that it projects to in contrast when I was looking at the healthy food there was a lot less activation and actually that that little dot there is not quite in the right place it's a little a little too far down so I'm not sure that's even the VTA so my brain clearly was not as interested in in the healthy food now was even more pronounced when we looked at my ventral striatum also known as nucleus accumbens so and these by the way these are really small brain regions so you shouldn't expect to see like a big blob but what you should look at is the level of activation and again if you look at the scale bar my ventral striatum was on fire when I was looking at that junk food and also again associated forebrain structures in contrast when I was looking at the healthy food there was not a whole lot going on you can see there's no activity whatsoever in my ventral striatum and this is actually typical of the studies that are done by my colleague Ellen Scherr who helped me with this experiment we our brains respond more to foods that are more calorie dense that are higher in these substances that I was talking about and particularly when we're in an energy depleted state so when you're hungry when your brain perceives that you're in an energy depleted state it doesn't want to eat low calorie foods it's not that interested in low calorie foods it wants to eat something really calorie dense that's gonna efficiently replete your your energy stores and you know what one thing I want to add that I forgot to mention in the earlier slides those substances that I was talking about that motivate us that the brain really pays attention to every single one of those is a form of carbohydrate fat or protein except salt that's the only exception on that list so the brain is very very attuned to substances that are delivering calories to the body presumably because of the evolutionary context where calories were a really important driver of natural selection and reproductive stress okay so what I've just shown you is that humans do have an intrinsic motivation for carbohydrate fat and protein we have the ability to learn which foods supply them through dopamine mediated reinforcement and we have the ability to tune our motivation level to match the value of the item because the amount of dopamine that's released is proportional to the concentration of those nutrients that are being detected in the gut so this satisfies all the criteria we were proposing earlier but now let's move on to the second section and look at which foods trigger cravings the most so we're all good scientists here so I'm gonna I'm gonna do a little bit of scientific method here and so we have our hypothesis I laid out my hypothesis in the previous section so now I'm gonna try to test that and the way you test a hypothesis is you make predictions based on it and then you see if the evidence corresponds to those predictions so here are my predictions I predict that foods that trigger the most dopamine release should trigger cravings the most those are foods that are concentrated in sugar, starch, fat, protein, salt, and glutamate and particularly that these things should trigger cravings when they're combined so when multiple reward buttons are being pushed by the same food that should trigger cravings even more so what I've done is I've done a little brief literature review and I've looked up papers that are relevant to this question in humans and there are a few different ways we can look at this but the two primary ways are one you just ask people what are the foods that you crave the most and then you rank them and the second one is you can look at addiction like behaviors which addiction is very similar to craving the mechanism is basically the same very similar and you can say which foods are driving your addiction like behaviors and then there's a third way I'm gonna throw in that's a lot more indirect and that is just saying what do people eat in the modern United States what's the average diet like and how well does that match up to the predictions that we might make based on the things that spike dopamine though in the first study researchers asked a thousand male and female college students what their most intensely craved foods were and this is a ranked list here we can see that number one is chocolate that's a pretty consistent finding then we have pizza then we have chips popcorn and pretzels ice cream sweets other than ice cream and then at the bottom not craved as often we have meat and chicken and bread and and pasta so there are a couple of things that are interesting about this first of all I think this is pretty consistent with the predictions overall at the top of the list we have foods that are very very calorie dense and our combinations of strong reward factors those substances that we were looking at earlier but there's another thing that I think is really interesting about the study and that is that we can look at sex differences though as you can see women in particular were drawn toward chocolate and this is kind of a stereotype but it's actually true there are a number of studies that have found this chocolate is very popular among men as well but not quite as popular as among women and actually if you go down that list you can see that for all of the sweet foods women crave them more often than men and furthermore if you look at the kind of savory fatty salty foods like pizza and meat those were craved more often by men than by women so there may be some sex differences in cravings for the second study researchers interviewed 108 healthy American women so this is specific to women about their food cravings and ranked them according to the most craved foods and this is the top 10 here again number one is chocolate pretty consistent finding number two is cookies cakes and pastries so far pretty consistent fresh fruit that's not really what the hypothesis would predict that's not a very calorie dense food it's not a mixture of different reward factors pretty much only has sugar ice cream Chinese food chips popcorn seafood beef lamb and veal dark green vegetables and nuts so this is kind of interesting because it's a mix I would say of things that the hypothesis would predict and a thing a mix of things that it wouldn't predict and the fresh fruit one really stands out to me because that's number three on the list that's really high up there and that's not an especially energy dense food and I'll be honest with you I don't really know how to explain that but what I will say is that it's not something that has been replicated in a lot of other studies so fresh fruit is not in other studies doesn't seem to come up very often as a commonly craved food I'm gonna show you one example of that here so this study was conducted by Ashley Gearhart who's really a pioneer in the field of food addiction and I'm gonna call it addiction like behavior or put the word addiction in quotes to recognize the fact that there's still ongoing scientific debate about whether foods are truly addictive or whether they just create behaviors that look a lot like addiction to drugs or whatever so just to recognize that that debate but the thing that I think is really cool about this study is that Gearhart and her colleagues gave people a list of 35 common foods and act asked them to rank them from top to bottom in terms of how much they triggered addiction like behaviors and the thing that's really cool about this is that we can look not only at the top of the list but we can look at the bottom of the list we could say what are the least craved foods and so what I've done here is I've copied and pasted the top 10 on the left and the bottom 10 on the right out of the total of 35 and so again chocolates number one no surprise there this is by the way this is men and women together ice cream french fries pizzas cookies chips cake buttered popcorn cheeseburgers and muffin this to me is is just exactly what the hypothesis predicts these are all extremely calorie dense combinations of concentrated rewarding nutrients that we saw in in the earlier slide now if we look at the least craved foods we have apples and bananas so that's too fresh fruit so that doesn't correspond to what we saw in the last slide we have plain corn salmon plain carrots plain brown rice water plain cucumber broccoli and plain beans so there are a couple of interesting things about this that I want to point out first of all you know obviously this is consistent with the hypothesis but the second thing I want to point out is those foods on the right you could make a healthy diet out of that I mean those foods are a lot better for you than the ones on the left if if if the entire American population only ate food selected from the right they'd probably be a lot healthier than they are today but those are not the foods that our brains are that interested in our brains are a lot more interested in the foods on the left at least on an instinctive craving level so the way our brains are wired to respond to these specific nutrients worked really well for our ancestors but it doesn't work that great in the modern environment where the foods on the left are very easy to acquire the final study I'm going to show you another study on addiction like behavior researchers administered questionnaires to 1495 Dutch college students asking about symptoms of food addiction and which types of foods were drove those symptoms the most and then they broke it down into four categories so high fat savory this is things like chips and fries and meat and cheese high fat sweet which is things like cake and chocolate and pastries low fat sweet or mainly sugar this is things like hard candy soda and dried fruit and low fat savory which is things like rice cakes crackers vegetables and bread and what you can see is that by far the most commonly reported cravings were for the high fat savory and the high fat sweet categories so again these are mixtures of concentrated rewarding nutrients there were many fewer people reporting cravings for foods that were primarily sugar and foods that were primarily low fat savory like bread and that sort of thing so people did report sorry I shouldn't say cravings addiction like behaviors so people did report addiction like behaviors to the mainly sugar and low fat savory categories but it was a lot less common and so I think this is also very consistent with the hypothesis that these calorie dense mixtures of these nutrients are the things that trigger the cravings and the addiction like behavior the most strongly the last source of data I'm going to consider is simply survey data on or I should say questionnaire data on the diet the typical diet of the US population so these are data from the USDA dietary guidelines for Americans report these are as of 2006 this is pretty credible data and they have these ranked in the order of greatest to least calorie contributions in the American diet this is the top 10 so these are the top 10 foods that are Americans are getting their calories from number one grain based desserts so this is things like pastries and cookies and cake I kid you not that is the number one source of calories in the US diet it's really pretty shocking yeast spreads bread is actually quite calorie dense we don't think about it that way because it's full of air but when you chew it the air goes away and it's very very dense in carbohydrate a lot of people also don't know this but it's the primary source of salt in the American diet chicken and chicken mixed dishes that includes fried chicken soda energy sports drinks in other words sugar water pizza booze pasta tortillas burritos tacos beef and beef mixed dishes and dairy desserts in other words ice cream so you know not all these foods I would say correspond exactly to what the hypothesis predicts but you have to consider that the brain doesn't just respond to dopamine the brain responds to a lot of different incentives and some of those are things like cost and convenience so we wouldn't expect our diets to only be driven by dopamine reinforcement however I think given that this list is actually quite consistent with dopamine playing a very key role in our behavior so just to review this section characteristics of food that commonly trigger craving and addiction like behavior are mixers of concentrated starch sugar fat protein salt and glutamate and the most commonly craved foods are fatty and sweet foods or fatty and savory foods such as cookies chocolate cake pastries and ice cream and pizza fried chicken cheese and chips low-fat savory and sweet foods are less common but still craved such as bread and crackers and hard candy and soda and so I think this is very consistent with the hypothesis that our food choices are guided in large part by dopamine release in the brain and this is a picture of the chemical structure of dopamine and the reason that our brains and our bodies are set up this way is that dopamine is responding to the food properties that kept our ancestors alive and fertile now I want to give a couple of brief tips on how to manage cravings so if you're trying to quit smoking you don't leave packs of cigarettes laying around you don't go to smoky bars you don't hang around with your friends who smoke you don't expose yourself to those cues these are cues that get your dopamine spiking and trigger cravings that can be hard to control so the first step is to limit your cue exposure and there are a lot of places cues can come from the food industry uses cues to try to ring Pavlov's bell and stimulate our motivation to purchase their foods so avoiding food cues on television and things like that is helpful and also controlling your food environment at home and at work so we do it to ourselves by exposing ourselves to food cues in our own kitchens and at our work so you don't want to expose yourself to the sight or the sound or sight or the smell or other cues associated with food especially foods that are tempting the second major principle is to focus on simple unrefined foods things like fruits meats vegetables oatmeal yogurt potatoes and sweet potatoes don't have the real high concentration of those nutrients that spike your dopamine and they're not gonna they're gonna be less likely to drive your motivation to an excessive level so just eat simple unrefined foods and one last tip I'll give you is that just like we forget all kinds of things in our lives we forget you know we learn all the state capitals and middle school and we gradually forget those we forget the 10th digit of pi but the non-conscious parts of the brain also forget and so those reward associations that you've formed if you don't continue to reinforce those by continuing to eating continuing to eat those foods they will gradually fade over time and have less and less power over you the take home points for the talk are most food cravings are simply dopamine reinforced motivations concentrated sugar starch fat protein salt and glutamate create and maintain cravings most commonly created foods are fatty and savory like chips or fatty and sweet like chocolate and to manage cravings limit your exposure to food cues and focus on simple unrefined foods I'd like to thank a few people who played key roles in this talk some people who did research that made large contributions to this are Anthony Scalfani even to Raho Wolfram Schultz and Ellen Schur Shizuka Aoki was the illustrator who I hired to do illustrations for my book I showed one of her illustrations earlier in the talk Ellen Schur Susan Melhorn Mary Ascorin and the University of Washington Diagnostic Imaging Sciences Center was kind enough to do that FMRI experiment on me and if you enjoyed this talk and you want to see more of my work you can go to stephengeana.com thank you Aaron Steffen excellent summary and review of what we know about the brain mechanisms the underlying cravings being an expert in the field of Pavlovian learning in those areas one thing I also know is that it's really hard once you acquire these associations it's really hard to extinguish them and they can persist for years so the forgetting point that you mentioned is good but one thing I want to maybe also raise is that the idea that maybe once a week once a month you know those of us on trying to follow whole foods paleo template type of diet say okay we're gonna have that what some people call cheat day or I'm gonna you know relax and have something I normally don't have those intermittent pairings can reactivate an old forgotten memory or even an extinguished association and re and it can come back full strength and so I just want everybody to realize that it could be very a very nefarious problem to try and really rid yourselves of the cravings you've acquired for these hyper palatable foods yeah thanks for that Aaron thanks for adding that and yeah it's really interesting and it raises a tough dilemma because you know at least from my perspective I don't I don't really want to be a drill sergeant with people I don't want to tell people don't ever eat you know a slice of pizza don't ever eat a brownie I want people to have a healthy relationship with food where they could eat it every now and then but I mean what you're saying is absolutely right and I think that's absolutely right and in fact I have a little anecdote about this those of you who have kids have probably experienced things like this but I have a friend who who has a son he's very young he's like one and a half maybe and they were trying to raise him on a healthy diet so they hadn't exposed him to a lot of unhealthy calorie dense foods like cake and stuff like that and while they were away on vacation my friend's dad was taking care of the child and gave him a little piece of a donut just a little piece like really little piece and the kid would not stop talking about it every day it was doughnut doughnut doughnut and and whenever my friend would have a bagel the kid thought it was a doughnut and so yeah those things they really make an impression on the brain it's very powerful yeah I hope that you include that part in the future talking about this because I think that's a real issue that we need to continue to get out there the thanks hi hey Aaron that's fantastic point because when you're counseling people on nutrition getting that through their heads like cheating is just shooting yourself in the foot is hard so getting out figure out how to convey the message in a way that any old anybody could get would be nice just want to ask you a quick question about the possibility of dopamine making fasting difficult and there's any research on if you could do dopatrophic supplements or anything to make fasting easier that's not something that I know anything about honestly sorry hopefully somebody will study that so I think there's a big difference in how easily people get addicted to things in general and how how easily or their tendency to crave things for example I personally and my father don't really get addicted very easily or crave things and I wondered if you think that a valid hypothesis might be that for people like me or for my from my dad would be maybe that our dopamine response is limited possibly we just don't maybe have a quick dopamine response maybe a little bit when we say brownie but on a screen but not so much I mean I mean sorry oh well I was on hospital last year in a car accident I got some heavy-duty medicine they were afraid to prescribe and my dad also had an experience similar where the drugs they gave him were you know the type of thing they were very controlled and for both of us it was very easy to stop it was not an issue at all and I talked to another doctor who was kind of amazed that I was able to stop as soon as the pain was gone yeah I was done no need so essentially there is individual variability in any almost any aspect of the dopamine and motivation system that you care to look at and a lot of its genetics so as you said there's very there's major how likely people are to become addicted in general and even how likely they are to become addicted to specific things so and a lot of that is genetic there's probably some that's not genetic as well but there's a very strong genetic component to it and this is actually something I talked about in my book as well okay you can actually and we and we don't by the way we don't really know a lot about what the specific brain mechanisms are that are mediating that okay but we do know that there is a very strong genetic component to it and would you say that the addiction and the craving aspect are are related for example I'm not someone who creates chocolate I get hungry you know I don't crave things yeah I mean we put labels on motivation and we call it different things in different contexts and when it has different levels of strength but it's all very similar process so there's a continuum from not caring about something to being totally and utterly addicted to it and that continuum includes you know healthy relationship it includes not caring healthy relationship with it craving it too much being addicted being predicted okay it's all the same process it's just different levels of dopamine and different levels of your ability to deal with that dopamine mediated reinforcement but it all comes down to dopamine dopamine is the essential mediator there that would determine how much you you either crave or are addicted to something yeah I don't want to say it's only dope okay I want to say that dopamine is a very very important element of it okay all right thank you thank you I appreciate so much of this especially the variety of data sources that you used and how you analyze them and your willingness to state your hypothesis before looking at them it but my favorite thing I think was the distinction you made between motivation that's hunger related and motivation that's not and it what the first thought I had about that was that this might signal or indicate the rarity of the availability of different foods while we were evolving and the idea that Aaron brought up with intermittent rewards makes a lot of sense there too but what I was wondering is if would also struck me was things that are motivated by hunger also seem to be demotivated by satiety that comes into play whereas the foods that yours that you're identifying is highly crave sensitive don't seem to have that satiety setting in can you speak to that yeah absolutely so there there are many additional levels of complexity that we could add to this system to that would be required to explain you know human eating behavior in real life but I think the certainly the hunger or energy homeostasis system is a big part of that and so and that has very strong interactions with the reward or craving system that I was talking about in this talk so if you are if your brain does not perceive that you have an energy needs so you're satiated then you're not going to be that interested in your average food that you might be interested in if you were hungry so something you know like a piece of plain meat or a boiled potato or unsalted nuts or something like that you're probably not going to be that interested in if you're full however as you were saying and and yes I agree with this there are some foods that are so motivating to us that they have a motivational ability that is that goes beyond hunger and is independent of hunger not completely independent I mean there is a level of satiety where you can reach it and you're like no I'm not gonna eat this no matter what it I'm not gonna eat this molten chocolate you know molten lava chocolate cake or whatever one struggles to imagine yeah there's a point but you have to get pretty far down the satiety line I mean you have to be pretty stuffed to get to that point for most people to say no to dessert but you don't have to be stuffed to say no to a boiled potato you just have to be full so yeah there they're really important interactions between those two things and again it's a continuum it's it's not black and white whether food is where food is going to fall in that continuum