The Sixth Sense of Taste

March 11, 2010 12:57 PM

Sweet, sour, bitter, salty, umami, and.... fat? Dr. Russell Keast, an Austrailian scientist who studies "perceived flavour, consumer acceptance and preference of foods and nutrition," has conducted research exploring humans' apparent sixth taste perception: fat. The kicker? Sensitivity to the taste of fat was negatively correlated with fat intake and BMI. Dr. Keast discussed the results of his latest research with Slashfood, and The Sydney Morning Herald. (via)

Some notable excerpts of Dr. Keast's statements about the latest research:

"We have sweet to identify carbohydrate/sugars, and umami to identify protein/amino acids, so we could expect a taste to identify the other macronutrient: fat."

''Fat has a very nice mouth feel to it [but it] appears that fat is activating something in the oral cavity independent of texture.''

And from the abstract:

...hypersensitivity [to oral fatty acids] was associated with lower energy and fat intakes, lower BMI and an increased ability to rank custards based on fat content.

...oral fatty acid hypersensitivity is associated with lower energy and fat intakes and BMI, and it may serve as a factor that influences fat consumption in human subjects.

And here's a PDF summary of Dr. Keast's earlier fat-taste research.

posted by sentient (31 comments total)

causal-direction-filter: Seems to me that it could also be the case that overweight people and/or those who have eaten more fat in their lives have become desensitized to the taste of fat. (Could test people on low-carb/high-fat-and-protein diets to investigate this a bit.) Apparently the research team is currently looking at what's responsible for the fat-taste-sensitivity, so perhaps we'll find out more. Interesting results, regardless.

Also.... Mmmm, custards.
posted by sentient at 12:58 PM on March 11, 2010

My mom hates the taste of fatty foods. She's thin. Take that as you may.
posted by mccarty.tim at 1:06 PM on March 11, 2010

Yes, about time fat was outed as a taste. It's not just the mouth-feel of fat food, it has a distinct taste.

Adding the concept of bouquet as a not yet used name for a flavor. The term is used for wine but I think many other foods have bouquet, in particular fruit. It's the delicate and sometimes complex taste of the aroma of flowers. Some fruits have more bouquet than others, such as lychees, nectarines, muscat grapes. But other foods also have bouquet to one degree or another, like certain cheeses, asparagus, sweet corn.
posted by nickyskye at 1:07 PM on March 11, 2010

My mom hates the taste of fatty foods. She's thin. Take that as you may.

Your anecdote seems to fit the hypothesis, not refute it. Skinny moms are expected to be more sensitive to the taste of fat. Fatty foods would taste "too fatty" to such people, in the same way salty foods might taste "too salty."
posted by explosion at 1:35 PM on March 11, 2010

Interesting. I have always been repelled by tasting fat . . . it does have a distinct flavor . . . and am the only woman in my family who hasn't struggled with weight problems.
posted by bearwife at 1:43 PM on March 11, 2010

I love fat, and yet am not fat. Take THAT.

nickyskye, "bouquet" is usually maybe more generally and specifically than your definition; it describes a multi-layered olefactory sensation that of course does affect flavor. It's an analogy to how many different flowers in a bouquet have individual scents yet create something new in their combination...but the bouquet of wine or fruit or cheese need not be floral. Or maybe I'm misunderstanding you?
posted by desuetude at 2:03 PM on March 11, 2010 [1 favorite]

I love the taste of it, and you could knock me over with a feather. I'm picky about my fatty stuff, butter yes, cream, no thanks. My SO laughs at me when he sees how much butter I can put on bread, and how often I can forego anything else on said bread, but I don't eat more fat in a day than he does if you look at how much of everything we eat.
posted by dabitch at 2:08 PM on March 11, 2010

I assumed that "hypersensitivity" doesn't mean "don't like it", but rather refers to simply being aware of fat in a food. In that case it wouldn't matter what you think about it, just that you're able to notice it.
posted by Greg_Ace at 2:22 PM on March 11, 2010

This is really fascinating. And I'm curious about the outcomes. Are we going to get 'stop tasting fat' meds? Are we going to get hideous fat replacer powder that we can put in our lean chicken wraps? Is this knowledge going to make our food culture better or worse off?

But I also came in to say: It's so weird that in these 'new correlation announced' threads, everyone writes, 'Yeah, yeah, well, but I'm x, and somehow I am not y.'

I mean, sure, that's cool. But you are a sample size of one. Take your data w/ a grain of salt.
posted by voronoi at 2:34 PM on March 11, 2010 [1 favorite]

When a whole bunch of people doing it, the sample size becomes larger than 1.
posted by dabitch at 2:40 PM on March 11, 2010

...For very large values of 1.
posted by Greg_Ace at 2:59 PM on March 11, 2010

Still, my sense is that people who are highly able to detect X in food do tend to be less fond of massive amounts of X in their food. I've known people, f'rinstance, who were seriously averse to bitter flavors, and sure enough they could taste traces of bitterness in things (lettuce, say) that I would never have recognized it in.
posted by nebulawindphone at 3:21 PM on March 11, 2010

(Also, — "But you are a sample size of one." — "When a whole bunch of people doing it, the sample size becomes larger than 1." — it's not just a matter of sample size. If A and B are significantly but weakly correlated, and there are six trillion people in the world, there are gonna be billions of A-but-not-B's running around.)
posted by nebulawindphone at 3:23 PM on March 11, 2010

I mean, sure, that's cool. But you are a sample size of one. Take your data w/ a grain of salt.

Of course! But what other thing can one say in response to a new study than to discuss anecdotal experience? We'll all have to wait to see if there is more scientific evidence in the future that debunks or supports this new research.
posted by bearwife at 3:24 PM on March 11, 2010

Dabitch, a million people could tell me that they are X but not Y and it still wouldn't give the slightest bit of evidence against (or for) the claim that X is correlated with Y. Now if you picked a random (or at least a good representative) selection of people and found that the proportions of X's who are also Y's isn't (or is) significantly higher than the product of the proportions of the X's and Y's in the group, then it would be relevant. But the people reporting here are far from randomly selected. Also, no one here is giving any notion of how common this hypersensitivity is. If it's really, really commonplace, then we'd expect there to be a lot of people who are hypersensitive and overweight, just not as many as you'd get if they weren't correlated. It's not just that there's not enough people. It's that no comparisons are being made and the sample is so far from being representative that it's ridiculous.

Also, I honestly wouldn't trust anyone (even myself) self-reporting that their sensitivity to "tasting" a substance is due to true "taste" (in the tastebud-activating sense) and not due to mouthfeel or the accompanying aroma, unless they've done some kind of test akin to what was done in this experiment. If it was so easy to tell the difference, we wouldn't still be discovering new tastes.

On a related note, the Slashfood article mentioned how they accounted for mouthfeel, but they didn't mention if there was any accounting for smell. Anyone here actually read the original article?

Regarding names for new flavors, I think that "fatty" probably covers it pretty well.
posted by ErWenn at 3:39 PM on March 11, 2010

nebulawindphone: If you look at supertasters, who have significantly more tastebuds than regular tasters and non-tasters and are correspondingly more sensitive to all flavors, you can see that while they do avoid bitterness (they rarely drink coffee or beer, for example), but this doesn't seem to apply to sweetness (I don't recall if there's a positive correlation or just the absence of a negative one).

I remember reading somewhere that while a preference for sweet foods seems to be innate, a preference for fatty foods is something that is developed over time. Does that ring a bell for anyone else?
posted by ErWenn at 3:45 PM on March 11, 2010

I wonder if extra sensitivity to fat can be learned, and if that could help people stick to a healthier diet.
posted by 5_13_23_42_69_666 at 3:58 PM on March 11, 2010

desuetude, Your definition of bouquet makes good sense, heh, when describing wine or the complexity of bouquet, that it includes a number of subtle flavors at one time, "a multi-layered olefactory sensation". The bouquet I'm referring to is distinctly a taste of the aroma of flowers. Muscat grapes, in my experience, taste like a meadow of wildflowers.

an analogy to how many different flowers in a bouquet have individual scents yet create something new in their combination

Nicely said.
posted by nickyskye at 4:03 PM on March 11, 2010

I also wonder whether people had to hold their noses while tasting the milk spiked (or not spiked) with fat-flavor... Is this truly a sixth fundamental flavor like the other ones, or is it just something else we can detect? Wiki says there's a receptor...

Are we going to get hideous fat replacer powder that we can put in our lean chicken wraps?

That's interesting... I wonder if "I can't believe it's not butter" uses something like that... It's also really difficult, in my opinion, to mentally separate the taste of fat from the texture. I guess it's possible to smell oil... But that's not really saying much.

I'm also inclined to agree that being sensitive to a flavor (like others have said, where sensitive = being able to discern or detect smaller amounts of the flavor) makes people not want to eat foods containing a lot of that flavor.

As long as anyone can think something is too salty, too sweet, too bitter (which are pretty common things to think), and thus not want as much of it, it makes sense that it works the same way with the fat-taste.

I do still wonder, like 5_13_23_42_69_666 was saying, whether sensitivity can wax and wane or vary over time. I know that not eating much sugar for a while makes you (me) more sensitive to it, in the sense that other people with think something is sweet enough, and I think it's too sweet, or unpleasantly sweet. Same with salty. That's part of why I wonder why hypersensitivity to fat flavor makes you thin, or not eating much fat makes you sensitive to fat's taste.
posted by sentient at 4:38 PM on March 11, 2010

Re: Names -- I think Arbuckle should be a name for it. :)

I consider myself a supertaster of bitter foods. I think I've gotten slightly better over time with it, but I still have problems with beer, veggies, etc... It seems that (and I believe, they even used the term in this article) this is a corollary for fat foods.

Is it possible that there's a relationship between bitter/fat supertasters? That is, are people who tend to be overweight (and who have an aversion to veggies) also don't taste the fat as much as those who may not be a veggie supertaster (and thus enjoy veggies) and dislike the taste of fat?

Prolly not, but something to be researched, I think.
posted by symbioid at 4:41 PM on March 11, 2010

. . .to rank custards based on fat content.


Wow, I want that job.
posted by TwelveTwo at 4:42 PM on March 11, 2010 [2 favorites]

Two possible reasons I can think of:

Fat people eat a lot of fat, and therefore their fat sensitivity is lower (or, they were more likely to have just eaten something fatty, causing the same thing)

People naturally want to feel like they've eaten X amount of fat. The more sensitive they are, the sooner they feel like they've had X, and therefore eat less.
posted by delmoi at 4:44 PM on March 11, 2010

Also I thought it was pretty obvious that we have fat sensors in our mouths. I'm kind of surprised it took this long for someone to say it "officially"
posted by delmoi at 4:47 PM on March 11, 2010

Oops:

"That's part of why I wonder why hypersensitivity to fat flavor makes you thin, or not eating much fat makes you sensitive to fat's taste."

should be

"That's part of why I wonder whether hypersensitivity to fat flavor makes you thin, or not eating much fat makes you sensitive to fat's taste."
posted by sentient at 5:02 PM on March 11, 2010

A supertaster experiences all tastes at a greater extent. So to call someone who is hypersensitive to a particular taste a "supertaster" is kind of an abuse of the word.

If you find yourself extra sensitive to bitter vegetables, there's another genetic factor at play, namely whether you have receptors that can taste phenylthiocarbamide, which is what makes broccoli and other vegetables taste bitter to some people (while others cannot taste it at all).

delmoi, why do you think it's obvious that we have tastebuds that can taste fat? What we call taste is influenced by so many factors other than what our tongues pick up chemically (mouthfeel, smell, even appearance), and there's really no reason for our brains to try and distinguish between the various ways we "taste" things. Personally, I'd never trust my own intuition about such things, so the fact that fatty things seem to have a fundamentally different taste to me than other foods doesn't seem to be very strong evidence that I must be tasting it with chemoreceptors on my tongue. If I followed that idea, I'd think that there were chemoreceptors for dozens of different tastes.
posted by ErWenn at 5:52 PM on March 11, 2010

Really good lard - which would be pure 100% fat, right? - is essentially tasteless. That fact alone is enough to make me wonder if "fat" (or "arbuckle" - I like that!) is truly a unique taste sense.

I can't get to the actual data on my computer, but the articles keep equating "umami" with meat and protein. I always associated umami with kelp, mushrooms, msg, and miso - so I'm not sure I trust these articles much. That, or I'm really wrong on what umami is. Or taste.
posted by kanewai at 7:13 PM on March 11, 2010

I did a hypoallergenic diet for a few months that involved no sugar and it was very low fat, low salt, no processed foods etc. I became very sensitive to all these tastes/sensations when they were re-introduced. Even oils/fats.
I used to be very overweight and would easily eat large quantities of foods with these traits without feeling satisfied. I definitely think you can re-set your body somewhat to be able to be more sensitive. It was hard but totally worth it.
posted by smartypantz at 8:18 PM on March 11, 2010

Just because there isn't a name for something doesn't mean that it doesn't exist...

In Cantonese, really good seafood (and in other food groups) has a flavour called "seine" (sounds close to scene, verbatim translation is close to "fresh") but there's no English language equivalent. Umami (a recent introduction to the English language) is close, but not the same. Salts of glutamate (MSG) doesn't have the same taste. The taste is "fishy" without the negative connatations of "fishy." There are fruit de mare that don't have an adequate taste description while limited to the English language. Strange.

Then again, maybe "fishy" is something that Asians find "good tasting" and Caucasians find revolting...?
posted by porpoise at 8:32 PM on March 11, 2010

sentient, hmm yeah that seems quite logical. Tasting fat = less fat = more sensitive to fat taste = eating even less fat.

Can't remember where I read it, but there was something about certain fats/protein strings found in moms milk and other fatty foods that trigger happy-centers in the brain, which explains why everyone seems to call the same foods comfort foods.

voronoi's idea of fat replacing powders (or sprays, like PAM, ugh!) probably isn't far from the truth. They'll be like "banana flavoring" is to the real banana I bet. Yuck.

Remind me not to try and be funny on metafilter again, by the way.
posted by dabitch at 1:00 AM on March 12, 2010

The bouquet I'm referring to is distinctly a taste of the aroma of flowers. Muscat grapes, in my experience, taste like a meadow of wildflowers.

nickyskye, yeah, I know what you mean. I think it's best described as "floral," though, which is more direct and keeps you from getting corrected by winesnobs. ;)
posted by desuetude at 6:35 AM on March 12, 2010

nickyskye, I'm with you on the bouquet thing. My favourites are fresh black tea leaves and steamed okra. Wine is ok, but I think I don't buy expensive enough wine. Granted, these are both "floral" bouquets. I don't know if steak has a bouquet, but sushi might.

Also, I'm pretty sure that this receptivity to "floral" bouquets can be learned. One of the cool things about studying botany is that you get to spend two afternoons a week with your face over a tray full of flowers preserved in 70% ethanol. I have very fond memories of the different bouquets that we... what? Inhaled? Were immersed in? After a while you realize that you're able to notice some very subtle flavourings. Loving the smell of EtOH probably helps...
posted by sneebler at 11:50 AM on March 12, 2010