http://www.abc.net.au/news/2016-01-...-intake/7098732

By Imogen Brennan

Eating a diet that is too high in fat may lead you to unintentionally reset your taste buds and set yourself up for overeating, say researchers at Deakin University.
Key points:

Tasting fat is needed to allow the stomach to feel full
High-fat diet can change taste buds and stop the person from tasting fat
Study also looking at whether genetics plays a role in ability to taste fat, by testing twins
Micro-scissors are used snip taste buds from participants' tongues

When people eat too much fat, their sensitivity to it decreases, meaning it will take more fat to satisfy their taste buds.

Now researchers say they have found that it is possible to change a person's threshold for tasting fat.

Professor Russell Keast from Deakin University's Centre of Advanced Sensory Science said when a person had a high fat diet and was overweight, they would be less sensitive to the taste of fat.

In the latest study published in the international journal Obesity, 53 overweight and obese people were put on a weight-loss diet for six weeks.

Some were given a low-fat diet, where less than 25 per cent of their total calories came from fat.

The others were put on a portion-controlled diet, where their calories were reduced, but 33 per cent of that intake came from fat.

Both groups of participants lost about the same amount of weight during the six weeks.

But only the people on the low-fat diet increased their sensitivity to fat, as well as the ability to identify fat in foods.

"It's some form of re-tuning or adaptation of the senses," Professor Keast said.

"When we get to a level where we can actually identify the taste of fat, it's actually very unpleasant."

People need to taste fat 'to feel full'

Professor Keast said what researchers were measuring in the mouth was also being reflected throughout the gut.

"If you require high concentrations to be able to identify fat in the oral cavity, the same thing is happening in your gut," he said.

If the nutrient is "invisible" to the taste buds and gut, it is difficult to feel satisfied and full after food.

"And this is a big part of stopping eating," Professor Keast said.

"One of the problems with dieting is the long-term sustainability.

"What we would be looking for in terms of strategies, is to increase the sensitivity with a low-fat diet, and then maintain high levels of activation of those fat receptors."
Harvesting tastebuds from twins

The Deakin University team is now studying whether genetics play a role in the ability to taste fat, or whether food intake is the only cause.

Deakin researcher Andrew Costanzo said for that part of the study they are studying sets of twins.

"We're putting one twin on a low-fat diet and the other twin on a high-fat diet to see whether or not fat taste is genetic, or there's some sort of environmental component to it which we can alter," Mr Costanzo said.

Part of the study involves harvesting tastebuds from the tongues of the participants.

They use micro-scissors to snip about eight taste buds from each of the participants' tongues.

"This is a completely painless procedure, it sounds much scarier than it is, but it doesn't have any effect on the tongue long term or short term," Mr Costanzo said.

"What we want to do is look at the physiology of the taste buds — how that changes from before to after the diet, and looking at exactly what part of the taste bud is involved in tasting fat."

The genetic research and the findings from the taste bud harvesting should be finished by the end of the year.

First of all, in what universe is 33% fat considered high fat?

Secondly, are they sure they're not talking about carbs?

Professor Keast would be shocked to learn the numbers of us here who have reached our goal weight while eating 70% or so of our calories from fat.

In other words, this so called research is the biggest load of garbage I've ever come across and I'm deeply ashamed it has come out of Australia.

Rotfl. Sometimes I wonder if you post these just to make us mad. I mean, look at this one:

It just occurred to me maybe this ain't real. Seriously, don't these guys have the intarwebs? They can't possibly be that blind to the rest of the world, especially the scientific world. Imagine they attend some lecture on ketogenic diets by some guy named Feinman or Fine. They just won't believe it, they couldn't even begin to grasp.

Don't you worry about Australia. We got some pretty good dumassery going on in Canada too, some straight from various Montreal U's.

I can vouch for the same in the US as well. This study should win some type of award, however, as the most successful at ignoring contradictory research in the rest of the world. You had me going until I saw your follow-up post!

So my years eating 70%+ fat, none of it from industrially produced oils, and my over 100 pound weight loss is just a fluke? I'm tired of this idiotic research designed solely to buttress the "low fat diet is best" hypothesis. No need to be ashamed, Roz. It could have come out of the US just as easily. It's not science it's propaganda.

Jean

I'd say so.

It's sort of obvious that on a higher fat diet, we'll have to become less sensitive to fat's satiating effects. Even when things are working right, even in a person not prone to obesity. If we were as sensitive to fat on a 40 percent fat diet as on a 20 percent fat diet, how would that work out? We'd get as much fat from a 1000 calorie diet at 40 percent as we'd have gotten from a 2000 calorie diet at 20 percent. The same can be said of sugar, if we base our diet on sugary foods, the body needs to become less sensitive to sweet, to protect against weight loss. It wouldn't do to have any one macronutrient individually and statically control our intake of a mixed diet, obviously as one increases, some other decreases, and we become more sensitive of the one and less of the other.

There are different mechanisms in place to keep us from over- or under-consuming protein, fat and carbohydrate. Part of the point of low carb, and how it works, might be that carbohydrate has lost its ability to satiate us. Sure, the higher the fat is as a percentage of calories, the more grams of fat it might take to satiate us--that doesn't mean necessarily that it will take more calories to satiate us.

Wait a minute. Fat can taste really bad if it's gone rancid. He's probably talking about veggie oil. I doubt he's talking about butter or lard or omg the fat streaks on an Angus rib steak or that thick slab of succulent fat on a nice pork sirloin. Oh my, bacon! Completely forgot about bacon. Butter coffee, ima make one right now. Ahhh, buttered toast, who can forget that from the days before LC! While we're at it, buttered hot muffin, some kind of hard cake, sandwich, peanut butter and butter on toast, butter and honey on toast, butter in soup like cream-of-stuff, on pasta, plain old mushrooms fried in butter, all kinds of other things fried in butter even my Angus rib steak, butter on that steak, butter on any steamed veggie like broccoli or something, butter on a nice hot oven baked potato, Hollandaise, crab and lobster with butter. OK, I'm done. Now take out all that butter. Tastes like cardboard. Every one of those things (oops, except that Angus steak, of course). OK, now instead of butter, add veggie oil. Just ain't the same without butter. In Quebec, we got this thing we call fèves au lard, beans with lard. Just ain't the same without that lard. Then it's just "fèves" or "beans". We got cretons too, it's a really fat pork spread.

What kind of recipes do Australians have that contain lots of fat like that? What kind of fat do they eat, is what I'm asking?

A search on Pubmed "fat detection threshold obesity" gives 13 studies. Mostly free fatty acids rather than triglyceride. Usually oleic acid, but I see lauric acid and omega 6 linoleic as well. These will probably be pharmaceutical-grade, so I don't know how likely they are to be rancid. Even something like butter though, it's breakdown products like butyric acid that make it taste so good. But too high a concentration of butyric acid, that would get pretty offensive.

See the researcher is right!
Notice how Martin is obsessed with fat?!

( not that I disagree! )
My wife is still convinced that fat is bad and likes to buy low fat hamburger on occasion. after eating lightly cooked 75% burger eating her over cooked 97% is an exercise in disapointment

Almost always when the headlines say "High Fat Diet" they're talking about a high carb/sugar diet.

If you've pre-programmed yourself to cringe at the thought of fat ever crossing your lips, then I would imagine that tasting the fat in your food might result in a negative response like this. What ever the taste happens to be, you don't like it because IT IS FAT. It is kind of like when I asked my young kids to try some new food. The fact that the food was new to them and that I had asked them to try it pretty much guaranteed that it was going to taste bad and they wouldn't like it. You could see it all over their face before the food got anywhere close to their lips.

Taste is acquired. We practice it, just like everything else we do. This means we can recognize things we've tasted before, and especially things we've tasted lots of times and in great quantity. The guy is looking at taste buds as if that's where the taste information is recorded and processed. Taste buds have no such ability. On the other hand, it's possible taste buds grow or change to increase their sensitivity to specific things, just like muscles and nerves grow in response to training and practice. But then if that's what happens to the sensing organs, something must happen to the recording and processing organ too - the brain. If there's more information being recorded, the recording/processing organ must also grow to accommodate the extra information. That's a problem for the brain cuz it's encased in a solid box, so it's got to use a trick, it reprograms itself at will.

But that's not what the guy says. He suggests taste buds actually decrease their sensitivity based on extensive practice. Eum, why would this sensing organ do the opposite of all other sensing organ, or any organ? The more often we sing, the better we get at it. The more often we listen to music, the better we are able to recognize it, notice subtleties, follow the beat, sing along, hum the tune, and so forth. The more stuff we watch, the better we get at seeing things. Smell, touch, motion, even abstract thought, all the same thing. The more we do it, the better we get at it. Why should taste be any different?

There's this idea where fat is satiating. So you eat lots of fat, then at some point this same fat becomes disgusting. Can't swallow another bite, you just gag. It's the same when you're hungry. The more hungry you are, the better the food tastes, regardless of what food it is. But then once you've had your fill, that same food just isn't appealing anymore. Can't eat another bite. OK, maybe that's what the guy is talking about, but I don't think so since he's talking about going from 25% fat to 33% fat, and within a semi-starvation diet. Let's try it ad libitum, from 25%, but this time right up to 90% or even 100% as in a fat fast, and with actual genuine food, not some lab chow. Sure, we don't control total intake, but isn't that the guy's point, that when people eat more fat, they eat more total food? Let's see if that hypothesis is true by allowing people to eat their fill, and more if that's the effect. I'm pretty sure it's not true.

To think some people sacrificed tastebuds to this ridiculous study.

Let me check my mayo supply. Don't want to run out

My daughter, in her mid twenties, started low carb eating about 4 months ago. I've noticed the evolution in her food interests, as in the beginning, she was very skittish about fatty meat. Now, she requests it and relishes it. In the beginning, she had a hard time using HWC in her coffee over half/half or light cream. Now, I've got to stock up on HWC, as it doesn't last long in my house if I don't. It reminded me of when I had to confront the concept of consuming more fat than protein and how I was skeptical at first. Once people get beyond the negative fat perception, there's nothing that tastes better in combination with other healthy food or alone on its own.

I believe this study shows selection bias and makes the assumption that fat tastes bad, and that to eat more, people must lose their taste sensitivity for fat. This is a very flawed assumption, as we've seen evidence through studies that fat combined with carbs as a fat delivery medium is a very unhealthy combination. And yes, it's easy to overeat when certain carbs are involved. I'm assuming the people conducting this study weren't very discriminating about fat/carb combinations. Fat alone or with some healthy protein or veggies? Marvelous!!!

To people accustomed to sickly sweet foods, adding too much industrial oil probably does taste unpleasant.

A better test would be to get people to see how much butter they can consume in the absence of sugar before it starts tasting unpleasant (I have never reached that threshold; it is my satiated stomach that shuts down eating it) and compare that to how much soybean oil, vegetable oil or even olive oil they can consume before the taste is unpleasant. And "taste" is a brain response. Thinking that something tastes unpleasant may just be feedback from the fat-regulating hormones telling the brain that you've chugged too much industrial oil.