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  #1   ^
Old Thu, Jul-13-17, 02:24
Demi's Avatar
Demi Demi is offline
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Default Blocking sense of smell causes weight loss

Quote:
From The Times
London, UK
13 July, 2017

Blocking sense of smell causes weight loss

Tom Whipple, Science Editor

The sense of smell has long been linked to taste. Airline food tastes worse because the dry cabin air makes it harder to smell, while people with colds often complain that food tastes bland.

Now scientists have claimed that the link is even deeper than that. They believe that if you can’t smell, not only are you less attracted to food, but you metabolise food differently — and it is less likely to make you fat. For a study published in the journal Cell Metabolism, a group of mice had their sense of smell blocked. For three months the impaired mice and normal mice were fed on a high-fat diet. At the end of that time, the mice that couldn’t smell weighed 16 per cent less than the other mice, which became obese.

The impaired mice were not eating less, nor exercising more. Instead the researchers, from the University of California, Berkeley, believe their bodies were doing fundamentally different things with the calories. While the normal mice were storing them as white fat, the ones that couldn’t smell had had their metabolism changed and were creating brown fat — which is quickly burnt off. They suspected that the bodies of the mice that couldn’t smell were tricked into using more energy.

Don’t invest in a clothes peg for your nose just yet, though. Humans have far less of a propensity to store brown fat than mice.

https://www.thetimes.co.uk/edition/...-loss-8zh9xw69f


Quote:
From The Times
London, UK
13 July, 2017

Scenting victory in the battle with obesity

Mice with no sense of smell can eat without getting fat, which looks like great news for humans

Jenni Russell


In the global fight against weight gain there’s no doubt who’s winning. The fat cells are coasting to victory everywhere. Worldwide obesity rates have more than doubled since 1980, according to the World Health Organisation: 40 per cent of all adults are now overweight or obese, and rising, and we don’t know how to reverse it.

People who eat less and move more can prevent themselves from gaining weight, but the same strategy rarely works to get rid of it. The gloomy fact is that bodies seem programmed to hang on to fat once we have it, with 80 per cent of dieters unable to maintain even a
5 per cent weight loss over five years. Only the drastic option of gastric surgery has a long-term record of success, with most patients losing half their excess weight. Good news for potential dieters is hard to find.

Until last week, when a group of American scientists came up with what could be the first big breakthrough in obesity research since laparoscopic bariatric surgery 20 years ago. A team at the University of California, Berkeley discovered that mice that had their sense of smell knocked out turned into fat-burning machines. They were given the same high-fat,
high-calorie diet as ordinary mice, and the normal mice doubled in size over three months, becoming obese. The smell-deficient mice ate just as much as the ordinary mice and were no more active, but stayed at a normal weight.

This was not remotely what the researchers had expected and they are as stunned by the results as everybody else. Andrew Dillin, the professor of cell and molecular biology who led the team, told me that they set out to test the role of smell in weight gain because it’s such an unexplored area. It is well known that people who lose their sense of smell get thin. The assumption has always been that they eat less because they are depressed, or because food becomes tasteless.

That was what the team thought they would document: mice that no longer cared for food. Instead they discovered a previously unknown link between what the brain smells and how the body prepares to process food. The sense of smell isn’t just a pleasure. It sends messages to the body which change its metabolism.

When the mice could smell nothing, they transformed their subcutaneous beige fat, the kind that accumulates around our hips and stomachs, into brown fat, which acts as a furnace to produce energy. They also lost substantial amounts of white fat, the dangerous variety which swaddles our organs. The normal mice, on the other hand, eating the same high-fat diet, not only grew obese but also developed the insulin resistance that leads
to diabetes.

That wasn’t all. The obese mice then had their smell capacity knocked out. They went on eating just as before but lost most of their excess weight and regained insulin control. Remarkably, they didn’t lose muscle, bone or organ mass, as is normally the case with dieters. They lost solely fat, an outcome that is the dieters’ holy grail.

This was the eureka moment for Dillin. When the results came in they were so surprising that he assumed the team “had made a mistake. So this paper has more controls and checks than anything I’ve done in my life.”

It is revolutionary because it snaps the link between calories in and calories out. It confirms that bodies are much more complex than that equation suggests.

Dillin tested his thesis, that the ability to smell our food makes us fatter, by going on to monitor mice bred to be super-smellers. He was proved right. The smell-sensitive mice got fat when they were fed the same food that kept ordinary mice slim.

The researchers’ theory is that our sense of smell is sharp when we are hungry, and dulled when we have been fed. If we can smell nothing the body takes it as a signal that we have eaten and have energy to burn, so it fires up. If our sense of smell remains acute, the body assumes we still need fuel and must store fat.

What everyone wants to know now is: what does this mean for us? Dillin thinks this could be “tremendously big” as long as he can develop a drug that temporarily kills off humans’ sense of smell without damaging anything else. He is “optimistically cautious” that there are enough similarities between mice brain circuits and humans for this to work, but will proceed very carefully, testing on dogs and pigs before any human trials. One red flag is that smell-deficient mice have high stress levels, often linked to heart attacks. He is already besieged by companies courting him, overtures he intends to ignore.

Dillin says his first priority would be the morbidly obese. Are they, he wonders, supersmellers? Do they crave 55 Snickers bars a day and get so fat because their olfactory systems are constantly signalling hunger? Their bodies and senses obviously operate differently to the rest of us; is smell the key to why?

This research offers hope to everyone; the enticing prospect of losing fat without willpower or lengthy deprivation. Dillin is full of hope but also fears the pitfalls. Might fast food companies develop a spray and fill their restaurants with it to make customers eat more? Might a drug encourage people to gorge? “It’s new and it’s a Pandora’s box,” he says, “and I want to be very very sure it works . . . But it’s one of those connections that now it’s there you wonder: why did we never think of this before?”

https://www.thetimes.co.uk/edition/...esity-chmkd26bg
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  #2   ^
Old Thu, Jul-13-17, 03:42
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JEY100 JEY100 is offline
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I smell a rat...or mouse..with this study without even reading. In 1990, during an operation on my hearing, my olfactory nerve was severed. There was a high likelihood of this happening but I accepted the risk. In that time since with almost no sense of smell, have gone up and down from normal weight to obese, and have been only able to lose and maintain with low carb diet.

And Dusty Homes make you fat? Is today April Fools Day?
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  #3   ^
Old Thu, Jul-13-17, 04:05
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teaser teaser is offline
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Seth Roberts' Shangri-la Diet fans have been clothes-pinning their noses for years. Seth's theory is that the bodyfat setpoint is set by food flavour, and that it involves a conditioned response. He was talking about flavour, not taste--he didn't count sweet taste, only smells etc., not that sweetness didn't count, it's just that the association of the sweetness with other aspects of the food was needed for the food to be fattening. So flavourless foods by this definition and foods that were new to the consumer so that a conditioned response to the food could not have yet been formed were supposedly non-fattening. Flavourless calories and fasting were supposed to decrease body fat setpoint.

Quote:
One red flag is that smell-deficient mice have high stress levels, often linked to heart attacks.


I was posting about this study in my journal the other day, in the conversation I brought up something I saw in a Robert Sapolsky lecture, a smell center in the brain was originally thought to be the emotional center--it turned out that this was due to smell being particularly salient to rats, these animals detect threats and mating possibilities etc. by smell to a much greater extent than humans, the same is true for mice. But "high stress levels," I wonder what they mean by that here? Fasting animals would have increases in certain stress hormones. This approach does have reduced exposure to a particular aspect of food in common with fasting.

Quote:
Dillin says his first priority would be the morbidly obese. Are they, he wonders, supersmellers? Do they crave 55 Snickers bars a day and get so fat because their olfactory systems are constantly signalling hunger? Their bodies and senses obviously operate differently to the rest of us; is smell the key to why?


Ugh. Read your own study. Supersmelling mice grew fat on food that didn't fatten normal mice. Supersmelling makes it easier to pick up a weak signal. A snickers bar is not a weak signal. There are a number of studies showing that bland, low flavour food, the sort that might only be detected as palatable by people with a strong sense of smell, rather than a weak one, are undereaten by overweight humans and rodents alike.

It would be interesting to see how the supersmeller mice would do on a ketogenic diet. Standard diet fed vs. fasted is not the same as ketogenically fed vs. fasted, you could see the decreased alteration in metabolism when somebody eats a ketogenic diet vs. when they eat a higher carbohydrate diet having an effect on this sort of conditioning. This would get us around the hard sell of claiming that a low carb diet works due to decreased palatability while still allowing for a weakened conditioned response.
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Old Thu, Jul-13-17, 04:09
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teaser teaser is offline
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Quote:
Originally Posted by JEY100
I smell a rat...or mouse..with this study without even reading. In 1990, during an operation on my hearing, my olfactory nerve was severed. There was a high likelihood of this happening but I accepted the risk. In that time since with almost no sense of smell, have gone up and down from normal weight to obese, and have been only able to lose and maintain with low carb diet.

And Dusty Homes make you fat? Is today April Fools Day?


One question I'd have here is how specific is this thing to smell, and how long the effect lasts. Pavlov's dogs salivating to the sound of a bell, all sorts of things might become associated with food, not just smells. Also as humans we have the option of increasing the signal from the other direction, compensating for a weaker sense of smell by eating smellier foods etc. I'm not saying you eat smelly food, just that there are ways to compensate. A lot of stuff we don't know.
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Old Thu, Jul-13-17, 05:06
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cotonpal cotonpal is offline
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Quote:
Only the drastic option of gastric surgery has a long-term record of success, with most patients losing half their excess weight. Good news for potential dieters is hard to find.


Somehow low carb diets get left out of the equation. Also this is not just about losing weight it is about maintaining weight loss. Looking for that holy grail of weight loss, that pill that is going to cure us all, leads to a kind of blindness of vision to what is already out there. What is the long term success rate of gastric bypass surgery? What is the complication rate?

Jean
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  #6   ^
Old Thu, Jul-13-17, 05:28
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JEY100 JEY100 is offline
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Quote:
Originally Posted by teaser
One question I'd have here is how specific is this thing to smell, and how long the effect lasts. Pavlov's dogs salivating to the sound of a bell, all sorts of things might become associated with food, not just smells. Also as humans we have the option of increasing the signal from the other direction, compensating for a weaker sense of smell by eating smellier foods etc. I'm not saying you eat smelly food, just that there are ways to compensate. A lot of stuff we don't know.

Visual cues way out-rank odor...why is everyone taking photos of their plates at restaurants? Hiring food stylists to out-do each other's Cookbook photos? Since I do the cooking, I can see and hear a crisp coating on a steak sizzling in a pan..I don't need to smell it. My taste buds also are muted, but I don't oversalt or eat weird stuff...as you said...the other senses step in.

Jean ,totally agree...and I hadn't even read that part...just thought this article was another piece of "fake science news"
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Old Thu, Jul-13-17, 06:06
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teaser teaser is offline
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Another thing. Make kittens where glasses with vertical stripes to a certain age, and keep them on a flat surface. Take the glasses off--they've learned what they've experienced, put them on a little platform, they'll walk right off and be surprised when they fall. Rodents are sometimes put in "enriched environments," and metabolically, they're very different then. But you could argue--compared to a cage, is the wild an enriched environment? Clearly it is--the intervention isn't the enrichment, it's the impoverished condition in the cage, that's looked at as the baseline, as if that's any kind of normal. We could think of the enriched environment as enriched, or we could think of it as just closer to normal--it's a non-impoverished environment.

Rat pups exposed to white noise develop seizures, this can be corrected by exposing them over time to a series of simple tones, giving the auditory cortex something to properly adapt to. Lack of specialization is the problem, any noise causes general activity, instead of activating a smaller number of neurons.

I look at chow as a "white noise" food. Out in the wild, eating various foods, various cues might be relied on for food learning. With something like chow, there's less information. A given volume of food has varied carbohydrate, calorie, protein, micronutrient etc. content in the wild. None of these things vary in the diet of a lab mouse. If associative learning affects how fattening a food is, these mice are definitely in an impoverished learning environment.
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Old Thu, Jul-13-17, 06:23
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cotonpal cotonpal is offline
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I have a friend who has no sense of smell. He has been this way since childhood I believe or at least through most of his adult years. He is in his 60's. He quite enjoys food. He is thin, always has been. He has an identical twin brother, also thin, but with a normal sense of smell who also enjoys his food. They are both about the same weight. What are we supposed to glean from this? For one thing it shows that food can be enjoyed both with and without a sense of smell and also that sense of smell doesn't necessarily have a major effect on weight.

I think Teaser's point about how we adapt to the environment we find ourselves in is an important one. Our reductionist science tends to erase the complexity of biological processes. First we cut out functioning stomachs of obese people and now we think about eliminating their sense of smell. I think this says more about how we think about obese people than it does about understanding what drives weight gain and loss.

Jean
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  #9   ^
Old Thu, Jul-13-17, 10:55
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WereBear WereBear is offline
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Quote:
Originally Posted by cotonpal
First we cut out functioning stomachs of obese people and now we think about eliminating their sense of smell. I think this says more about how we think about obese people than it does about understanding what drives weight gain and loss.

Jean


I completely agree. If you delve down into gastric bypass, as I have done, the picture is hardly reassuring.

While you have "only" a 1 in 200 chance of dying from the procedure, the aftermath is different. The surgeon is going to dust you off his hands within six months, while the "honeymoon period" lasts a year. The honeymoon is the time period for your digestive system to fully heal... and properly feel hunger again.

Typically, this first year is a time when the procedure works as advertised. People aren't hungry and the weight is dropping off. Many of them find the exacting regimen of tiny meals and required vitamins an easier price to pay than their many failed diets, and the nearly inevitable bathroom difficulties and bouts of stomach spasm and lightheadedness are compensated by their rapid weight loss and the admiration from family and friends.

Some don't even get that though; if there was any kind of emotional content to their eating, that coping mechanism is now gone, never to return. A 2012 survey indicated people after bypass had doubled their risk of alcoholism. Other "emotional eaters" discover that stuff like ice cream and cake digests more easily than fat and protein. It is less likely to trigger "dumping," which some people describe as "feeling like you are going to die." The internet is full of bariatric foods, basically Atkins bars and shakes for bypass patients, because real food is just so troublesome.

And then the honeymoon ends. Hunger comes back. And there's not a dang thing you can do about it. This is the "failed bypass" where people gain back all the weight by stretching their stomach back into a larger size. And if they are lucky, that is the end of it.

But a substantial number (at least a third, but of course they don't like to release real data) go on to have far more serious issues, including death. Because this is also when the consequences of nutritional absorption come in; the compromised digestive system can't absorb nutrients so matter how many vitamins and shakes a person tries to get down. Eat more, dodge the complications, and gain weight. Don't eat more, and make malabsorption more of a problem.

So then there's epilepsy, nerve damage, strokes, brittle bones, joint pain, dimming vision, mental disorders; the list goes on and on.

Successful? I don't think so.
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