Eating Psychology

Are we all just food-selecting zombies?

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It was a Saturday afternoon- I spent all morning writing one of my dissertation articles. It was unfortunate that i had to be on campus instead of enjoying my morning coffee at home, but some syncing error got me panicking as I couldn’t find my latest saved draft.. So here I was with only 25 minutes before my aerial fitness class: I made a quick stop at an empty campus store, grabbed something to eat and rushed out to my car, still deeply pensive over some changes I should make- I am writing about lay interpretations of healthy eating context.

I looked down to see what it is I was holding in my hand, because it seemed like i made my snack choice in some auto-pilot mode: fullsizerender-20

OK, it made sense. Considering the context. And then I thought- I just spent 4 hours writing up my article on healthful eating beliefs.. how would I go about finding out what rationale was behind my food selection right now?

I pretended to ask myself in an interview format- “why did you choose these items?”- and immediately imagined a word cloud of my transcribed answer: there was a whole bunch of stuff there, but several most salient words stood out: calories, protein, satiety, light. The transcribed text would read:

“…so I was not starving yet, but it was almost 1pm and I had an intensive aerial class that I anticipated i’d want energy for… i needed to feel full but not physically full (so, light)- can’t eat anything big before hanging upside down on the aerial hoop! I know protein is satiating, and I like this bar because it’s damn delicious (i’m aware of the halo effect that “protein” has in this situation – extrapolating the “goodness” of protein to unrelated product characteristics, such as it’s overall healthiness… it’s really just a candy bar! but the health claims on the package do pacify the guilt splendidly). I also know that sweetness may provoke hunger on it’s own, so I have to balance the taste with the umami-ness of string cheese. This combo is also just about 300 calories, which is my upper limit for a snack (I gage it, though I know i’m exactly on point with the number despite not checking the nutrition label)… I don’t really count calories- I think it’s not a helpful behavior and one can become fixated on it, which might get detrimental for your dietary quality. Yet I also can’t help being somewhat vigilant- I know eating gets more “fun” later in the day, so I want to leave enough of an energetic allowance to indulge in my evening netflix/playstation time. Calories definitely matter- i’m so tired of people’s hopeful attempts to fight this truth and discover a loophole in the first law of thermodynamics. Sure, there are nuances- cooking and processing can change the availability of calories to your body, but those are just nuances to me- at least that’s my current stance based on the literature.”

Wow, that’s a whole lot of rationale for an “auto-pilot” choice that took 20 seconds without conscious effort. Of course, eating perceptions and choices are my research topic, so I am quick to self-reflect in detail. Yet for many respondents, who hold their own complex mental models of healthy eating, this can be like pulling teeth- it’s not easy to explain things that seem obvious or natural to us (unless maybe you’re writing a dissertation on it). My reasons are good examples of cognitive heuristics- “rules of thumb” used to make choices in complex situations, such as eating (we make about 200 eating decisions daily, according to Dr. Wansink- too lazy to give you the specific study name.. just google it 🙂 ) The “Protein- satiety- good” connection is a simple heuristic, the “power” and “energy” words on the bar signaled appropriateness of this snack before a workout, the familiarity of the products (I know this bar and it’s taste; bought it before) also played a role.

But anyway: I’m almost done writing my first chapter now. I’m in the process of shortening it actually……… by about 10,000 words :S It’s such a painful process to let go of your findings- perhaps I’ll post a bunch of interesting results here in the coming months! I could be sporadically posting cool quotes on twitter or Instagram too, but honestly- that’d get attention of maybe 10 people. Meanwhile my latest quick sketch of a friend pulling off an aerial trick just got more than 1000 likes… So forcing myself to tweet the dissertation is lacking in motivation at the moment. In the meantime- enjoy whatever it is you might be eating right now! Don’t overanalyze it, I suppose?

UPDATE:

I stopped by the campus store on this fine “dissertating” morning, and got the protein bar again + another item to illustrate my previous point. This probably won’t shock anyone, but i’d say i was quite correct in stating 2 days earlier “it’s really just a candy bar!”

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The protein bar’s serving size says “1 COOKIE”. Cookie! Kit Kat has the decency to refer to itself as 1 package 😀 Surely, both are just candies.

At least if you consider the energy content and, really, majority of ingredients (i will admit- “monk fruit” sounds mysteriously awesome, though it is the last ingredient (so there’s like a trace amount of it).

Now, obviously there’s a difference- and that’s the difference that drives the high price point of the protein bar (as well as it’s healthiness message): the power bar has more protein (13 g vs. 3) and less sugars (5g vs 21g). On another hand, the power bar has a bit more saturated fat and cholesterol. That last point is most likely less relevant to an average reader- so far, my interviews and surveys show people vilify sugar much more than fat (again, you’re probably not shocked and i’m definitely not the first one to notice- the low fat fad is over, it’s been all about the horror of carbs for awhile).

Now, protein appears to be more satiating than sugar, according to a bunch of studies (go check out Google Scholar), so perhaps you indeed might eat more later after the Kit Kat, despite eating the same amount of calories as from the Power Bar. And something like that can be tested in a nicely designed experimental study (probably has been). Despite all of this, next time i make a quick stop at the store, i’ll probably still reach for the  Power Crunch bar. Buying a Kit Kat is too bizarre- I  don’t eat candy! And though i know the bar is really just another candy- well,  it just leads to less cognitive dissonance 😛

 

 

Shall we Snack?

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How we think about the food we eat matters. Really matters. The way you categorize your food- whether it qualifies as a meal or a snack- can influence whether & how much you will eat later that day.

Today we talked about snacks in the psychology of eating class. My personal cross-cultural observation of snacking between Ukraine and US is that Americans tend to snack more often.. they snack in various situations (at work, in class, on the run) and some believe snacking throughout the day is beneficial for weight maintenance. This perception comes from the idea that eating more small meals throughout the day (snacking) will keep your metabolism up or keep your hunger down. While it does elevate your metabolism somewhat, the problem is that most people can’t seem to eat “small” meals throughout the day… instead they end up simply eating all day long. In terms of hunger management.. it is quite individualistic- perhaps having a snack truly makes you less hungry throughout the day…or it makes you even hungrier (now, that depends on the snack too; carb-rich snacks tend to make us hungrier after consumption…and we can argue that processed foods have an addictive quality where you just have to finish the whole bag).

SNACK vs. MEAL

What’s a snack? Usually something small or in pieces.. it is eaten between meals. If you’re surprised by how someone might confuse a meal with a snack- people do think differently about which is which…some foods can be seen as both by different people- e.g. pizza or bagels (hey, some eat cereal for dinner!). Generally, though, “snack food” is perceived as food  not consumed to satiation (versus a meal); it also involves eating alone and for a short period of time.

A study by the ASU provost/my psychology professor Capaldi* showed that the cognitive feature of food (whether you perceive it as being part of a meal or a snack) moderates food intake regardless of hunger and satiety following a load. In simpler terms- if people ate the same amount of calories, but perceived the food as a SNACK, they ate more afterwards (even though their satiety level was the same as for those consuming the same food only seen as a MEAL). It has to do with norms- we feel it is much more appropriate to eat a full meal after some snacking then after a meal.

PROBLEMATIC DEFINITION
So your categorization of food might be important for how much you eat…This might be a problem with the way eating has evolved lately. Meals are generally seen as a sit-down occasion with utensil use…but in the hectic modern life your lunches and dinners might not involve a plate, fork, or even sitting down to eat. As a result, you might not register your lunch as a satiating meal and feel the need to eat later. Indeed, taking the time to eat in a calm atmosphere might make you feel more satisfied with your meal (has anyone else ever felt like they didn’t really eat if they grabbed something on the fly? I definitely do).

Shall we snack!? Currently,  evidence does not support many theories that encourage increasing frequency of eating for weight management**. Some suggest that snacking is one of the main causes of overconsumption and obesity***. In the end, you can’t recommend the whole population to either snack frequently or avoid it altogether. Some might find snacking to keep their appetite down.. while for others it may be difficult to control food quantities once they commence eating.  I suppose you should go with your gut and be mindful of whatever you are eating 😉

* Capaldi, E. D., Owens, J. Q., & Privitera, G. J. (2006). Isocaloric meal and snack foods differentially affect eating behavior. Appetite, 46(2), 117-123.

**Palmer, M. A., Capra, S., & Baines, S. K. (2011). To Snack or Not to Snack: What should we advise for weight management?. Nutrition & Dietetics, 68(1), 60-64.

***Buchholz, T. G. (2003). Burger, fries and lawyers: the beef behind obesity lawsuits. US Chamber of Commerce, US Chamber Institute for Legal Reform.

Monotony makes you..slimmer?

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This week we were discussing SENSORY SPECIFIC SATIETY in our psychology class and.. I find it fascinating!

Why do we stop eating? Because we got enough calories/feel full/got the right nutrients? Looks like we stop food intake cognitively– by knowing that we ate enough and knowing when it is appropriate to stop [studies on folks with short-term memory loss, it was found that they would eat the meal several times despite having a large meal already, when most of us would report being full at that point]

SSS within a meal

Sensory specific satiety (SSS) basically means you get tired of the taste&texture of food (studies show it happens even if you don’t swallow the food; thus it is not about getting full on calories). To be a bit more scientific in my definition: “as food is consumed, its pleasantness declines while that of other foods remains relatively unchanged”; this phenomenon of SSS leads to the termination of eating a particular food, while promoting the selection of other foods. So after being destructively full after a large meal..many would suddenly find “space” for a dessert.Image

The studies done with SSS show that if you sit down people for lunch and give them several small sandwiches with different flavors of cream cheeses, people will eat considerably more than if all those sandwiches had only one flavor (even if that flavor is a favorite of the individual). Other example is that people eat more of pasta if their bowl had more types/shapes of it. SSS does not mean that you stop wanting food- it means you don’t want more of the same food. For example, after a meal of x, y, z you are given more y… the person would say “thank you I am full”… vs. being given h– something you have not developed sensory satiety for and will still eat (therefore, all you can eat buffets are not such a wonderful idea;)

So truly, this is a great adaptation, because it motivates us to eat a variety of things. It also means that, if our meals has a large variety (in its texture & flavor) we tend to eat more. This is not particularly useful, though, in an environment where delicious food is available 24/7 and one looks to maintain a healthy weight. Think about many sauces or salad dressings that combine both strong sweet and salty tastes (thus, making sure we don’t get satiated as soon..and probably eat more).

SSS seems to work well with fats and proteins, but not so much with basic starches. What this means is that people don’t get sick of eating bread, pasta, and other starchy carbs over time. 

SSS over time…

So far I talked about short-term SSS, or satiety with one meal; however the same is true when the same food is eaten over time (i’m sure you’ve experienced this- if you keep eating the same thing daily you might get tired of it), even though long-term SSS is more complicated. The study I read*, for example, looked at eating high energy-dense snack foods for 12 weeks (hazelnuts, chocolate, potato chips). While people’s sensory-specific satiety decreased (they liked them less) over time, the desire to eat these foods didn’t…and intake increased. So habitually eating high calorie snacks could lead to higher energy intake of the snack and weight gain. You don’t really want to have a low threshold for SSS- that means you don’t get sick of foods and may overeat them more.

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Why I find this interesting? It makes me think of dieting…most dieting restricts something– carbs, fats, certain ingredients (gluten; dairy). When people see weight loss, perhaps it is because the more narrow range of foods leads them to quicker sensory satiety and then overall they just eat less? Many diet plans emphasize calculating calories is not important, as if you can eat way over your limit and not gain weight..but perhaps you naturally are lead to consume less because of the monotony of the diet? 

Another thought I had- mono-eating= eating one food at a time until you are food. The idea is- it is better for digestion, but also- looks like you would limit your food intake much more naturally (with less effort) when not having a variety in one meal. 

Overall, I think this is quite interesting. While we want a healthy variety in our diet, we probably want to concentrate it on the vegetables and other healthy foods we don’t get enough of. Variety in ice-cream and chip flavors is probably not essential at this time and age.

*Tey, S. L., Brown, R. C., Gray, A. R., Chisholm, A. W., & Delahunty, C. M. (2012). Long-term consumption of high energy-dense snack foods on sensory-specific satiety and intake. The American journal of clinical nutrition, 95(5), 1038-1047.

*** for more info on SSS, search for papers by Barbara Rolls.

U[mmm]ami.

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Some people claim they “crave” protein in their food to feel satisfied… others say it is really the fat that they are after. Do we really crave protein? Can we even “taste” protein in itself?

I used to think that we do not.. until we got on the topic of UMAMI in class. In 1908 Kikunae Ikeda identified the unique taste component of kelp (seaweed) as the salt of glutamic acid (most abundant amino acid in the diet). He used umami(=”savoury deliciousness”)  to describe it, which to a Westerner translates to meaty, broth-like, savoury. Other umami substances are0 inosinate and guanylate

pic_umami_01Umami- the 5th Taste

Glutamate is found in both animal and plant foods; in almost all protein-containing foods (fish, meat, poultry, eggs, cheese), many vegetables (ripe tomatoes, cabbage, maize, green asparagus) and for humans & chimps, in mother’s milk. In addition, glutamate is produced by our bodies and binds with other amino acids to form structural proteins.

The taste of glutamate (on its own + in combination with IMP5 ribonucleotide) is thought to represent the taste of protein (evidence is still scarce). Glutamate has a special quality of enhancing certain flavor characteristics of food (sugar, salt, fat). * Umami, by the way, is tasted by humans and dogs (rats can’t seem to taste it as much). Currently, umami is recognized as the 5th basic taste (others: salt, sour, bitter, sweet)

Wait a second…Glutamate!?

If you’re at all into health, the word “glutamate” has probably evoked some negative connotations. Or- monosodium glutamate- the evil MSG. While umami exists naturally, MSG is a additive (extracted glutamate mixed with salt) which has become quite unpopular in the 90s due to health concerns (for health issues, please google MSG; that’s a whole other topic). If you use MSG, you taste umami, but umami does not contain MSG (MSG on its own does not taste good but enhances flavor of other foods). I suppose the original idea was to add umami-tasting MSG to healthy but often disliked foods such as bitter vegetables to increase their intake…of course  now you find MSG in many processed nutritionally poor products (it’s probably not too great to increase our liking of those foods).

UnknownIn conclusion….can we crave protein specifically? Indeed it seems so. The study I reference at the bottom argues that the taste of MSG maybe one of the compounds that represents the taste of dietary protein…this “meaty” umami taste appears to predict the liking and preference for high protein foods.

In fact, I now realize why seaweed, especially dulce flakes were quite popular with my raw vegan friends. We just loved seaweed– it seemed to fill us up when added to raw vegetable dishes. I suppose the umami taste, which is associated with meatiness and richness, might impose the feeling of satisfaction with one’s meal. Note: This website has a fantastic post about umami & being vegan!: http://www.theveganrd.com/2012/04/is-umami-a-secret-ingredient-of-vegan-activism.html

Opinion: While clinical studies do not support the negative health claims of MSG, we could always be weary of natural compounds being extracted and concentrated in unnatural amounts.  So far, it seems that any time a human tries to improve on nature in a lab, the results tend to be disappointing. Want to experience more umami- add sun-dried tomatoes/miso/organic soy sauce to your dish instead (mmm) ;D

*Luscombe-Marsh, N. D., Smeets, A. J. P. G., & Westerterp-Plantenga, M. S. (2008). Taste sensitivity for monosodium glutamate and an increased liking of dietary protein. The British journal of nutrition, 99(4), 904–8. doi:10.1017/S000711450788295X

What makes us FULL? (macronutrient perspective)

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Sometime in the semester, I heard people speak about satiety (satiation is the process of feeling full & terminating food ingestion during the course of eating) in relation to protein and fat (protein apparently is more satiating, even though fat has more calories).  Feeling of fullness is important- it is one of the problems I faced as a raw vegan, which made sticking to the lifestyle very hard long-term (I was raw vegan for ~2 years).

So instead of preparing for class tomorrow, I am reading up on satiety! Some main points:

Most importantly- it’s not all about the calories, since not all calories are treated equally by the body.  The hierarchy of fullness is the following: Protein > Carbs > Fats. So, protein satiates more than carbohydrates, and fat is least satiating (which came as a surprise to me considering it has most calories per weight). High-fat foods have a weak effect on satiation.

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Within the macronutrient categories, we find differences too: not all carbs exert the same effect on satiety (fiber has been consistently shown to have a higher satiety value vs. simple sugars), and neither does fat (the medium-chain triglycerites [e.g. the wonderful coconut oil] seem to be more satiating).

Of course, people don’t eat only to get full. The number 1 reason given for eating a certain food is taste. More specifically- palatability (subjective pleasantness of food). Low-energy-dense foods tend to be less palatable, but more satiating :/

According to the article*, ideally our diet would consist of low-energy-dense foods with high palatability (unfortunately such foods are not very common). This “diet” is one low in fat, has adequate protein and fiber, and includes lots of fruits, vegetables (so food with high water content).

Of course, focusing on whole foods vs. processed makes lots & lots of sense- a whole food product takes time to chew and digests longer (satiety signals are maintained for longer).

Apart from specific studies, common sense must prevail: staying away from “fat” is not necessary (not as much as staying away from processed fat, vegetable oils, etc…), and adding great fats (e.g. avocado!) to meals is both healthy and filling (studies show that while fat on its own is least satiating, it’s power to fill us up increases when it is added to carbs).

Feeling full is important! Constantly feeling deprived could potentially lead to overeatingand more stress.

P.S. I shall probably post more on the subject of satiety later, considering I have a whole class coming up on this topic 😀

*Gerstein, D. E., Woodward-Lopez, G., Evans, A. E., Kelsey, K., & Drewnowski, A. (2004). Clarifying concepts about macronutrients’ effects on satiation and satiety. Journal of the American Dietetic Association, 104(7), 1151–3. doi:10.1016/j.jada.2004.04.027

“Listen to your body”?

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Could your body “tell” you what to eat due to its health state? If you’re deficient in a certain nutrient…will you instinctively crave foods with that nutrient?

Many believers in the “body wisdom” would say yes. Actually, i think the idea of body wisdom is extremely popular- I myself know this from the raw diet, and I am sure many alternative “natural” diets talk about this concept (e.g. intuitive eating?). Unknown

I think it is fascinating- that’s why I was excited to talk about this in my psychology of eating class. I tried to find a relevant peer-reviewed article for class discussion, but to my surprise found nothing. In class I understood why- there is no evidence for body wisdom in the literature. There originally was an idea that our bodies can tell what we are deficient in and gravitate towards foods with those nutrients- first rat studies seemed to prove that.  They had rats on a thiamine deficient diet choose between two new diets- one with thiamine, or the previous thiamine deficient one. The rats chose the thiamine diet. They could tell they needed vitamin B1, right? Not really- turns out the rats avoided the same thiamine-deficient diet not because they could sense the deficiency, but due to the learning that the original diet made them somehow sick.  Animals, thus, avoid eating whatever doesn’t make them feel good. They, like we, learn to eat what makes us feel good. The only thing you can have a specific hunger for (so you’d be able to choose food with that particular nutrient in it) is salt- it is easy to taste/identify and we have a genetically preprogrammed specific hunger to it.

Generalist vs. specialist?

When you think about it, animals seem to KNOW what to eat, what’s good for them (I hear people argue we have that ability too, or “body wisdom”). But let’s think about it…an animal that specializes in one kind of food (e.g. carnivore, insectivore) has a very narrow range of foods..they must get all essential elements from those foods= the identification of food can be programmed genetically into them. But for a species that eats anything(or “generalist” animals)– e.g. humans– the problem of finding food can be less demanding since there are many potential sources..and eating a nutritionally balanced diet can be achieved in many ways. Perhaps that’s why our body wisdom is not as acute- we are not dealing with a narrow range of foods. (See Paul Rozin for more)

SO?

I don’t know whether specific body wisdom really exists- the one that can signal you to eat a certain food because of a B vitamin you’re low on. Either way, I think we have access to a different kind of wisdom- choosing whole unprocessed foods is much closer to our evolved physiology than any of the new created foods that seem to be destroying our health. Apple vs. apple juice- that seems wise 😀

Eat healthy for healthy kids!

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Looks like a varied healthy diet is important before a kid is even able to eat solid foods. Specifically, it is important for pregnant and breastfeeding mothers, since a child’s first experiences of flavor occurs prior to birth through milk feeding and amniotic fluid in utero.

SO eating a variety of vegetables and fruits influences acceptance of these foods at the weaning stage (~5.7 months).

Breastfeeding is crucial (vs. formula-feeding), since it prepares kids for novel flavors through the mother’s diet being transmitted to milk [Flavors so far known to be transmitted through breast milk are garlic, ethanol, carrot, mint, blue cheese, and cigarettes]. If formula-feeding is the only option, it is important to switch formula flavors and types to allow for variety.

Conclusion: varied diet in pregnancy and during breastfeeding is recommended.  Some suggest that up to 6 month is the period we are most sensitive at for introduction of different flavours..and that we are never again as open to new experiences!*

Note: repeated exposure to one flavor can become monotonous and actually decrease liking in a child.. so that would be counterproductive (again, variety is good!).

Lastly..

Being overweight or having a “junk” diet (for mothers) can be potentially detrimental for kids.

1. Being overweight/obese is a risk.. The problem- overeating and obesity during pregnancy lead to in utero overnutrition..and can cause the development of obesity in the adult offspring (even when the child had normal feeding and lactation).

During pregnancy leptin resistance and hyperphagia occur, which lead to increased deposition of fat.. In lean individuals this is a great adaptation allowing mothers to store energy in preparation for lactation (a high metabolic demand activity).. But in the current “obesogenic” environment this adaptation would make it hard for women to regulate their food intake (especially those predisposed to obesity).**

2. While I haven’t found a study on humans, studies on rats show that rats born to mothers fed junk food during gestation & lactation developed an increased preference for sugary, fatty, and salty foods; they also exhibited increased weight and BMI. Data from numerous studies shows that maternal junk food diet can change the ofsprings’ epigenetic marks related with long-term changes in gene expression (opiods & dopamine) and behavior (stronger preferences for palatable foods- sugar/fat/salt).***

* Article doi:10.1016/j.appet.2011.05.317

** Article doi: 10.1210/en.2008-1106

*** Article doi:10.1210/en.2010-050

Loving it healthy!

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Reading yet more articles on the psychology of eating…

How do we learn to like certain foods?

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Well, we learn when it makes us feel good (we feel full, the sweet taste is pleasant), because other people do so (we model behavior of others, eat what our culture things is appropriate), and because it’s something we’ve eaten many times (we’re exposed to a certain food since childhood).

Food neophobia is the fear of new foods in kids (starts ~ age 2). It’s an important trait since it serves a protective function (you can get poisoned by eating unknown foods), but at this time in history with diverse food environment it might limit kids’ diet for the worst.

Learning through exposure (repeated tasting) is a way to make young children eat food that they don’t seem to like. [Between 50-60% of variance in preference for foods in 4-year olds is explained by its sweetness and degree of familiarity!]

For a 2 year old, ~10 attempts might be necessary to make them like a new food (usually vegetable 🙂 It’s important to space these attempts and be persistent (most parents just give up after trying to give one food several times). So e.g. you can give a red pepper in small portions daily over the course of the week and eventually your kid will like it!

The number of attempts goes up with age ( 4-year old- ~15 attempts; 10-year old- up to twenty exposures to the food may be necessary).

You want your kid to enjoy vegetables later in life- start them early by giving it to them at a young age and don’t give up 😀

Psychology of Eating

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Just out of my Psychology of eating seminar and wanted to jot down a couple of new things I’ve learned.

We were talking about Flavor-Flavor learning- you can learn to like a certain food/flavor by pairing it with the flavor you already like (adding sugar [sweet flavor] to oatmeal). This is quite useful to humans as a “short cut” for eating foods that are safe and energy dense and avoiding potentially harmful ones= sweetness is preferred since in nature a fruit would also have an array of valuable micronutrients important for health; bitter taste is disliked since it is associated with poisonous foods, etc.

Either way, here are a couple of interesting facts I learned today-

CALCIUM makes things taste bitter; thus lots of leafy-green vegetables are not liked by people. But you can learn to like them if you pair these vegetables with, for example, sweetness or fats (think of a green smoothie kale+banana+nut butter).

ImageAlso, adding sugar to bitter foods makes them taste less bitter; adding sour- more bitter.

Most recent meal is associated with fullness, so if you eat a regular meal followed by dessert- you will associate dessert with fullness. To associate healthier foods with satiety, eat dessert first! 🙂 

It is important to remember that virtually ALL of our food preferences are learned rather than innate, so you can teach yourself to eat healthier by liking it more!