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Secrets of Math From the Bee Whisperer

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Scarlett Howard has taught honeybees how to add, subtract and understand zero. Their ingenuity suggests that all animals may have more mathematical talent than we thought. – photo credit: Anne Moffat for Quanta

Susan D’Agostino writes in Quanta:

carlett Howard teaches math to honeybees. She began with a few hives on a concrete balcony at RMIT University in Melbourne, when she was a doctoral candidate in zoology. Today, at the University of Toulouse, where she is a postdoctoral fellow, her lessons take place in a small field with approximately 50 hives.

It might seem a little strange — bees are insects, after all; what do they know about mathematics? A lot, it turns out. These eusocial flying insects can add, subtract and even comprehend the concept of zero.

“You can see their decision-making process in their movements and flight patterns,” Howard said. While deciding which of two answers is correct, they often fly toward one of the solutions before seeming to think better of it and flying off toward the other.

Howard teaches one bee at a time, placing it next to an apparatus known as a Y maze, a covered box shaped like a block letter Y. The bee enters the bottom leg of the Y and sees a mathematical question, expressed in shapes and colors. In the arithmetic lessons, blue shapes mean “add 1” to the given number of shapes, and yellow shapes mean “subtract 1.” To answer the question, the bee chooses from one of two possible solutions posted at the entrances to the Y’s upper arms. The bee will find a reward — sugar water — in the arm associated with the correct answer, and a punishment — tonic water, which bees find bitter — in the arm with the incorrect answer.

To teach bees about zero, she first trained them to understand the concept of “less than.” As with the addition and subtraction problems, she offered reinforcements for correct choices. Once an individual bee demonstrated it understood “less than,” she advanced that bee to the testing phase of her experiment, where it would decide if any number of shapes is less than zero shapes — a number the bee had never encountered before. Each bee had only one chance to answer. The bees often identified “zero shapes” as smaller than any number of shapes, and Howard concluded that they must possess an innate understanding that zero is smaller than any positive integer.

For each experiment, Howard trains and tests approximately 100 random bees from the thousands in her hives. Handling them is simple enough. After each correct choice, the bee flies back to the hive on its own, to offload its sweet reward. Then, at some point, it’ll come back. That’s because bees are central place foragers, meaning they will remember the experiment and return to it for additional resources. To prepare for her next pupil, Howard changes the stimuli on the Y maze. She has hundreds, possibly thousands of stimuli printed and laminated.

“They’re laminated so we can clean them with ethanol, because bees will scent-mark,” said Howard. “They’ll do anything to cheat the tests. They’re smart! They’ll mark the correct answer. Bees are not as simple as we used to think they are. Or even as some people still think they are.”

Quanta Magazine recently spoke with Howard about her research. The interview has been condensed and edited for clarity.

What first inspired you to research bees’ mathematical abilities? Were you a fan of the bugs?

I had always been really scared of bees. But when I was at university in Australia, Adrian Dyer, who works on bees’ cognitive abilities, told me, “Bees can do really cool things. They can recognize human faces and navigate mazes.” I thought, “Really? Is that true? I want to see that for myself.” So I pitched the idea of working on bees’ cognitive abilities to my potential Ph.D. supervisors.

We thought, “We can do something either really high-risk/high-reward, or we can do something less risky but less interesting.” We tried something risky first — whether bees could understand zero at the same level as some primates and birds do.

Most animals know, for example, whether or not they have “some food” or “zero food” in front of them. Do bees really possess more than this basic understanding of zero?

Bees are able to place zero within a numerical continuum. They know that zero is less than 1, it’s less than 2 and it’s less than 3. They also know that zero is more “less than 6” than it is “less than 1.”

Many animals have difficulty with zero. The number 1 might have been the lowest number they’d ever seen. When we got positive results from that experiment showing that they knew zero is lower than any positive integer, it was really exciting to see.

Of course, different bees have different processes of learning. Some do really well from the beginning. Some are really quite bad. You see this moment where they start to get things more and more right. You don’t want to anthropomorphize them too much, but it’s really incredible to watch how they learn.

Wait — some bees are better at math than other bees? . . .

Continue reading.

Written by LeisureGuy

22 January 2020 at 2:29 pm

Posted in Daily life, Math, Science

Migraines through history

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Landscape with Aura, from the Migraine Action Art Collection, 1981.
Courtesy Migraine Action Art Collection (463)/Wellcome Collection.

Katherine Foxhall writes in History Today:

Migraine affects one in seven of the world’s population – approximately a billion people. The World Health Organisation calculates it to be the seventh most disabling among all global diseases, more prevalent than diabetes, epilepsy and asthma combined. Virtually everyone will live with, work with, be related to, or be friends with someone who has migraine. But how, over the centuries, have people interpreted, explained and treated this disease?

What is migraine?

The writer and broadcaster A.L. Kennedy has described migraine as ‘a ghost, it’s a gaoler, it’s a thief, a semi-perpetual dark companion’. Rudyard Kipling, on the other hand, wrote in a letter that it was ‘a lovely thing’, though it divided him in two: ‘One half of my head … throbs and hammers and sizzles and bangs and swears while the other half – calm and collected – takes notes of the agonies next door.’

There are many types of migraine. Migraine without aura is most common. Characterised by severe pain, often in one side of the head, attacks can last from a few hours to three days and often include nausea and vomiting. Before and during a migraine attack, many people experience various other symptoms, such as tiredness, emotional disturbance, poor concentration and sensitivity to light or sound. Migraine with aura involves additional neurological symptoms, most commonly a visual aura lasting between five and 30 minutes. Many people see a C-shaped zigzag pattern that spreads across the field of vision. Aura can affect any of the senses, manifesting as vertigo, tinnitus, reduced hearing, pins and needles, whistling sounds, numbness or speech disturbance. On average, migraine sufferers experience one or two attacks a month, but around two per cent of the world’s population has chronic migraine, classified by the International Headache Society as headaches that occur for 15 or more days per month (of which eight are migrainous), for three months or more.

Migraine affects women two to three times more than men, is common among children and seems to be more prevalent among people with low socio-economic status. As well as the pain and discomfort of each attack, the cumulative effect of migraine can bear on all aspects of daily life, affecting relationships with family, partners, friends and work. We know that migraine involves nerve pathways and chemicals in the brain and it seems likely that the headache pain comes from neurogenic inflammation. But much remains unknown about migraine, including its cause and the extent to which antimigraine drugs can access the brain. It is this uncertainty which makes understanding migraine’s history so important.

A migraine by any other name

For nearly 2,000 years, people have talked about a disorder called migraine. In the second century ad, the Roman physician, surgeon and philosopher Galen used hemicrania to describe a pain that affected half the head and was caused by rising vapours from bilious humours in the stomach. Through translation and use, Galen’s term spread. We find emigranea in Latin and Middle English, migran in medieval Welsh. The early modern period saw many variations on the English ‘megrim’ or ‘meagrim’. Galen’s term also provides the common root for migraine in a variety of languages, including migräne (German), migraña (Spanish), migréna (Czech and Hungarian) and, of course, the French migraine. . .

Continue reading.

Written by LeisureGuy

21 January 2020 at 9:13 am

Life without design

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Chiara Marletto, a postdoctoral research associate and junior research fellow at Wolfson College at the University of Oxford, writes in Aeon:

Living things have puzzled and challenged us since the dawn of our species. Even in the light of our modern scientific understanding, they seem remarkable. A merlin falcon hunting its prey, a hummingbird suspended in the air beside a flower, the self-reproduction of a bacterial cell: all are instances of stunning control and precision. How could anything so complex have originated from inert matter?

For millennia, some of the most brilliant thinkers have attempted to answer this question. Most of them concluded that living things must have been produced by an intentional design process. They were wrong, of course: the theory of evolution by variation and natural selection – Charles Darwin’s momentous leap – shows how those stupendously intricate mechanisms can come about without one. Yet the task of showing how life itself can arise without design is surprisingly vexed.

The very problem Darwin’s theory addresses is ultimately rooted in physics: living things have certain properties that seem to set them apart from other aggregations of inert matter. They have many different subparts – instantiating biological adaptations – all coordinating to some function. That’s the key property: they closely resemble objects that have literally been designed, such as factories and robots. For example, the ciliary muscles and the lens in the eye coordinate exquisitely to permit vision, just like the optical components of a sophisticated camera. In modern biology, this is called the appearance of design – a property described by Socrates and given canonical expression in 1802 by William Paley in his ‘watchmaker’ argument for the existence of God.

More generally, living things, again just like factories and robots, have the ability to perform physical transformations with a very high degree of precision, and to do so repeatedly and reliably. A goat’s jaws and heart just keep on chewing and beating for its whole lifetime. If you got the goat to graze your lawn, it would mow it to high accuracy and be just as capable of doing the same when presented with another lawn. It just keeps going: the goat is, among other things, a lawnmowing machine.

Unlike factories, all living things rely on a rather peculiar contrivance: the living cell. Cells can self-reproduce, manufacturing new instances of themselves in a process involving, at its heart, the faithful replication of the genetic information contained in the cell’s DNA. We find this capacity nowhere in the rest of nature. Even among human technologies, there are only dim foreshadowings of it, such as 3D printers that print some of their own spare parts.

Why should such features of living things constitute a problem for physics? Crucially, what can and cannot be made to happen in the physical world is determined by physical laws. For example, a perpetual motion machine cannot be constructed, no matter what resources are devoted to the task, as it is forbidden by those laws. Conversely, given the presence of life in our universe, physics must be such as to allow for it.

But our laws of physics provide only certain elementary objects, such as simple chemicals, in great numbers. These objects do not, in themselves, have the ability to repeatedly cause highly accurate transformations. Neither do they seem adapted to do anything in particular. If they do cause transformations, it is neither very accurately nor reliably: they wear out and make errors, their resources get depleted, and so on. In other words, the laws of physics contain no built-in facility for accurate transformations; nor, in particular, for biological adaptations that can bring such transformations about. They are no-design, in this special sense. Thus the problem with living things, expressed within physics, is that they are highly adapted to effect all sorts of transformations to high accuracy, whereas the laws of physics aren’t.

Given that life isn’t the output of an intentional design process, but evolved, how could living things have evolved given these design-free laws of physics? Darwin’s theory addresses this problem, explaining that variation and natural selection bring about the appearance of design. But this in itself doesn’t close the explanatory gap, as we can see especially clearly in the modern version of Darwin’s theory – neo-Darwinism. At its heart are the replicators, or genes – bits of DNA that are transmitted, by replication, to the next generation. Moreover, for replication to be as accurate as it is in living things, accurate self-reproduction of the cell is also required. In short, the theory presupposes the possibility of certain accurate physical transformations, and these are just what no-design laws of physics fail to provide in their starter kit.

Here’s where the puzzle arises. Biological replication and self‑reproduction are in fact such stupendously well‑orchestrated physical transformations that one must explain how they are possible under the simple, no‑design laws of physics such as ours. This additional explanation, which was not included in the theory of evolution, is essential for that theory to properly explain how living things arise without intentional design – to close the explanatory gap.

Now, it turns out that an explanation of this sort is peculiarly difficult to formulate using the prevailing methods of physics. The latter can predict only what a physical system will do (or will probably do) at a later time, given certain initial conditions and laws of motion. But applying laws of motion to particles is an intractably laborious way to express the appearance of design, replication, self‑reproduction and natural selection. Those processes are highly emergent, involving the collective motion of countless interacting particles.

There is more. Even if one could predict that – given certain dynamical laws and initial conditions – particles would aggregate so as to form a goat at a certain time, this would not at all explain whether a goat could have come about without design. The design of the goat, for all we know, could be encoded in the initial conditions or in the laws of motion. In general, one must explain whether and how a goat is possible (ie, permitted) under no‑design laws of physics; not just predict that it will (or will probably) happen, given some version of the actual laws and initial conditions.

Thinking within the prevailing conception has led some physicists – including the 1963 Nobel Prize-winner Eugene Wigner and the late US-born quantum physicist David Bohm – to conclude that the laws of physics must be tailored to produce biological adaptations in general. This is amazingly erroneous. If it were true, physical theories would have to be patched up with ‘design-bearing’ additions, in the initial conditions or the laws of motion, or both, and the whole explanatory content of Darwinian evolution would be lost.

So, how can we explain physically how replication and self reproduction are possible, given laws that contain no hidden designs, if the prevailing conception’s tools are inadequate?

By applying a new fundamental theory of physics: constructor theory.

Constructor theory is a mode of explanation proposed by David Deutsch, visiting professor of physics at the University of Oxford, who pioneered the theory of the universal quantum computer. With constructor theory, Deutsch generalises some of the insights that led to that earlier idea, applying them now to the whole of physics.

In constructor theory, physical laws are formulated only in terms of which tasks are possible (with arbitrarily high accuracy, reliability, and repeatability), and which are impossible, and why – as opposed to what happens, and what does not happen, given dynamical laws and initial conditions. A task is impossible if there is a law of physics that forbids it. Otherwise, it is possible – which means that a constructor for that task – an object that causes the task to occur and retains the ability to cause it again – can be approximated arbitrarily well in reality. Car factories, robots and living cells are all accurate approximations to constructors.

This radical change of perspective is consistent with current explanations in terms of initial conditions and laws of motion, but permits . . .

Continue reading.

Written by LeisureGuy

21 January 2020 at 4:16 am

Posted in Daily life, Evolution, Memes

A doctor talks about his switch from low-carb/keto diet to whole-food plant-based diet

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And as blog readers know, I also was able to discontinue all my medications (for diabetes, for high blood pressure, and for cholesterol control) 10 weeks after switching from a low-carb diet to a whole-food plant-based diet.

Written by LeisureGuy

20 January 2020 at 9:17 pm

New program aims to break taboo by teaching high school students about endometriosis

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Comprehensive sex education programs that begin in early education and include some instruction each year can help students a lot as they grow and mature. Wendy Leung reports in the Globe & Mail:

Endometriosis is a common condition that affects an estimated one in 10 females of reproductive age. But because few discuss the symptoms or regard the severe pain and nausea during menstruation as abnormal, many suffer for years before getting treatment.

Now, researchers at BC Women’s Hospital and Health Centre have launched an experimental program to teach high-school students about endometriosis as part of their sexual-health curriculum.

They hope the one-hour sessions, taught to students at New Westminster Secondary School, will help adolescents recognize what’s normal and what’s not during menstruation, and encourage them to seek help if they experience symptoms.

“What we’re trying to advocate is also empowerment of young females in terms of taking charge of their health,” said Catherine Allaire, medical director of the Centre for Pelvic Pain and Endometriosis at BC Women’s.

Endometriosis occurs when endometrial tissue, which normally lines the interior of the uterus, grows outside of the uterus, which can lead to the formation of lesions, cysts and other growths. Symptoms, which may include severe menstrual cramps, nausea, vomiting, irritable bowels and diarrhea, can cause individuals to miss school or work. Pain can also occur outside of menstruation, such as during ovulation or during sex, Allaire said.

But due in part to taboos around talking about menstruation, there is often an eight-year delay between the onset of symptoms and receiving a diagnosis of endometriosis, she said.

“A young female that is having all these symptoms may not know that it’s not the norm or may not know what to do about it,” she said, adding that when young women do speak up, their symptoms are often dismissed by family members or even health professionals.

More than 60 per cent of women with endometriosis report encountering at least one health professional who dismissed their symptoms, Allaire said.

The in-class sessions are based on a menstrual health and endometriosis educational program in New Zealand, which has been shown to increase students’ awareness about the condition and potentially lead young women to seek specialized health-care services sooner.

The researchers at BC Women’s have partnered with Options for Sexual Health (Planned Parenthood’s affiliate in B.C.) to deliver the lessons to a total of roughly 100 students, grades 8 to 12, as part of a pilot study. The first group of around 20 Grade 12 students participated in a session last month, and the team aims to have four or five more classes each undergo a session early this year. The study is funded by the Michael Smith Foundation for Health Research.

Kristen Gilbert, education director of Options for Sexual Health who is teaching the sessions, said the classes include students of all genders.

“All of us know people who have periods, even if we don’t [have them],” she said, adding in the first class, all the students were interested and engaged.

One student, in particular, informed her afterward that she would share what she learned with a friend, whose menstrual symptoms included vomiting.

“So it wasn’t just that student in the class who’s going to benefit from that lesson. It’s her whole circle,” Gilbert said.

Teacher Chelsie Goodchild, whose Grade 12 anatomy and physiology class participated in that first session, said her students typically learn about the reproductive system in school, but endometriosis is generally not a topic that is covered.

Goodchild said the session was not only informative for her students, but for her as well. Later, when she discussed the study with her parents, she learned her own mother had endometriosis.

“It was pretty eye-opening,” she said. . .

Continue reading.

Later in the article:

. . . Had she learned about endometriosis in high school, Bridge-Cook said she likely would have realized much sooner that the pain she experienced during menstruation was abnormal. Even though she began having symptoms at age 13, the first she heard about endometriosis was when she was in her 20s. She was not diagnosed until she was 34. (A surgical procedure called a laparoscopy is needed to receive an accurate diagnosis.)

The pain became so debilitating when she was in her 30s, she was unable to work for about three years. After four surgeries and a combination of strategies, including nutritional changes, pelvic physiotherapy and medications, she is now able to manage her symptoms but still has chronic pain, partly because her endometriosis was untreated for so long. . .

Written by LeisureGuy

20 January 2020 at 2:07 pm

The weak influence of the “obesity gene”

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Also from How Not to Diet:

To date, about one hundred genetic markers have been linked to obesity, but when you put all of them together, they account for less than 3 percent of the difference in body mass index between people.52 The “fat gene” you may have heard about (called FTO, short for “FaT mass and Obesity associated”) is the gene most strongly linked to obesity,53 but it explains less than 1 percent of the difference between people (a mere 0.34 percent).54

FTO codes for a brain protein that appears to affect your appetite.55 Are you one of the billion people on Earth who carry a full complement of FTO susceptibility genes?56 It doesn’t really matter, because this only appears to result in a difference in intake of a few hundred extra calories a year,57 while what it took to lead to the obesity epidemic is more like a few hundred calories a day.58 FTO is the gene so far known to have the most effect on excessive weight gain,59 but the chances of accurately predicting obesity risk based on FTO status are only slightly better than flipping a coin.60

When it comes to obesity, the power of your genes is nothing compared to the power of your fork. Even the small influence the FTO gene does have appears to be weaker among those who are physically active61 and may be abolished completely in those eating healthier diets. FTO appears to affect only those eat diet higher in saturated fat (predominantly found in dairy, meat, and junk food). Those eating more healthfully appear to be at no greater risk of weight gain even if they inherited the “fat gene” from both their parents.62

As Dr. Greger observes, “obesity does tend to run in families, but so do lousy diets.”

Written by LeisureGuy

19 January 2020 at 6:25 pm

The ileal brake and fiber-rich food

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I have assumed that the reason that I’m able to restrict my eating to a 4-hour window (for me, 10:00am to 12:00pm) and be not at all ravenous when 10:00am rolls round, just a bit peckish and inclined to have a bite of something, was that I avoid refined/processed food (very little if any dietary fiber) and meat, dairy, and eggs (zero fiber) and instead eat whole plant-based foods, and those have a good amount of dietary fiber.

Moreover, I refrigerate (intact whole) grain and beans after I’ve cooked them, and the refrigeration makes part of the starch resistant so that it acts like dietary fiber, making down to the large intestine and (like fiber) nourishing the gut microbiome.

I assumed that the fiber and the resistant starch were why I did not feel terribly hungry, but I didn’t know the mechanism, just my observation that I did not get desperately hungry and my guess at the reason.

I’m now reading How Not to Diet, and I came across this interesting passage that explains the mechanism:

A review entitled “Food Fibre as an Obstacle to Energy Intake” summarized what I call the Four Ds by which dietary fiber results in reduced caloric intake:1205 dilution of calories by expanding the volume of food, distention of the stomach through fluid absorption, delay in stomach emptying of the gelled mass, and dumping of calories by blocking the absorption of other macronutrients, such as carbs and fat. That fourth D triggers a fifth phenomenon known as the ileal brake.

The ileum is the last part of the small intestine before it empties into the colon. When undigested calories are detected that far down our intestines, our bodies put the brakes on eating more by curbing our appetites. This can be shown experimentally. If you insert a nine-foot tube down people’s throats and drip in protein, fat, or sugar, you can activate the ileal brake. Then, if you sit them down to an all-you-can-eat meal, they will eat at least one hundred fewer calories than those in the placebo group who had only gotten a squirt of water through the tube.1206 Activating the ileal brake can make people feel full up to nearly two hundred calories earlier. [And I think the calories in the resistant starch activate the ileal brake. – LG]

Ever since its discovery, the ileal brake has been considered a medical target for appetite control. So did doctors simply advise patients to eat lots of whole, unprocessed plant foods so that the fiber would drag calories down to activate the brake? Not quite. Instead, they developed the first major bariatric surgery, the jejunoileal bypass.

Fiber-depleted foods get absorbed quickly and never make it all the way down to the ileum, but instead of having people eat foods in their natural form, some doctors decided just to cut out the intervening twenty or so feet of intestine. By attaching the end of the ileum right up to within about eighteen inches of the stomach, the ileal brake is activated no matter what you eat. It’s like your emergency brake is always on. You can still drive, but not as fast. So, with the jejunoileal bypass, you can still eat, but not as much because you’re already feeling full.

More than twenty-five thousand patients underwent the procedure in the United States before it was realized that cutting out 90 percent of the intestines wasn’t such a good idea. The jejunoileal bypass resulted in long-term progressive liver scarring in 38 percent of patients.1207 That’s nearly two out of every five patients. Though the surgical approach failed, the medical mind-set still prevails, with researchers teaming up with drug companies and the food industry to exploit the ileal brake for weight loss with “dietary encapsulation or slow release strategies,”1208 failing to recognize that Mother Nature already designed a natural strategy in the form of fiber-rich food.

Intestinal Workout

There are many ways eating more fiber means eating fewer calories, but the “Dietary Fiber and Weight Regulation” review found that study subjects randomized to consume higher-fiber diets lost more weight even when caloric intake was fixed.1209 Think about it: more weight loss even when prescribed the same number of calories. So if it wasn’t the calories-in side of the equation, could it be the calories-out side? Normally, calories out means things like exercise, but, in the case of high-fiber diets, there are literally calories out—as in out the other end and flushed down the toilet. But the same-calorie, higher-fiber groups were losing more weight even after taking into account the excess calorie dumping. Where were the calories going? 

To solve the mystery of the missing calories, researchers fed people different amounts of fiber and sealed them in an airtight chamber called a whole-body calorimeter to closely monitor their metabolic rates.1210 Those with more fiber in their systems burned more calories—even in their sleep. Though it was only about 2 percent more, that translated into about fifty more calories burned a day without getting out of bed. What was going on? . . .

He goes on to answer that question, but the answer I was looking for is covered: because the starch is resistant, some of it reaches the ileum still containing noticeable calories, which activates the ileal brake — so I don’t feel hungry.

Pretty cool.

Also note this about dietary fiber (from the same book):

Crowding Out Calories

The first major review, “Dietary Fiber and Weight Regulation,” included a dozen interventional studies in which people were randomized into higher-or lower-fiber diets. The additional consumption of fourteen grams of fiber a day led to an average weight loss of 1.9 kilograms over 3.8 months.1183 That’s only about a pound a month, but the weight loss was greater among those who needed it; overweight and obese study subjects lost triple the weight compared to lean individuals. How much is fourteen grams of fiber? Not much. Fourteen grams would barely bring the average American’s diet up to the recommended minimum average adequate daily fiber intake.1184

The increased fiber intake appeared to lead to about a 10 percent drop in daily caloric intake.1185 Why would more fiber mean fewer calories? Well, conventionally, fiber is considered to have zero calories, so it adds bulk to food without adding extra calories. To illustrate, let’s compare a food to its fiber-depleted equivalent. Consider a bottle of cold-pressed apple juice, which is basically an apple with its fiber removed. You could chug a regular 15.2-ounce bottle of juice in a matter of seconds, but to get the same number of calories, you would have to eat nearly five cups of apple slices.1186,1187 Which do you think would fill you up more? Obviously, the apple slices. But why?

First, you’d need to chew every apple slice. Fiber-rich foods require more chewing, slowing down eating rate, which itself can improve satiety.1188 This also allows for more secretion of saliva and stomach juices. In one study, researchers spread a barium paste onto slices of different kinds of bread and found that, upon x-ray, the stomach shadow was larger after eating whole-wheat compared to white bread, showing how much fuller you physically get.1189 So, in our cold-pressed apple juice versus apple slices scenario, we have the extra fluid secretion on top of the five cups of slices pushing on the walls of the stomach, which has nerves with stretch receptors that can send fullness signals directly to the brain.1190

One type of fiber in apples is pectin, the gelling agent used to make jams and jellies. Imagine how eating all those apples would not only add a lot of extra bulky volume but could start to form a gel to further slow the rate at which those five cups of slices left your stomach. This would keep you feeling fuller for longer compared to consuming the same number of apple calories in fiber-depleted juice form, which would pass right through you much more rapidly. Other gummy fibers like those found in oats can have the same gelling effect. Five grams of a highly gelling fiber can hold approximately one quart of water as it passes through the stomach and small intestine, so that’s like having an extra two pounds of zero-calorie food mass filling you up.1191

Obviously, juice is going to drain out of your stomach faster than apples, but even the same volume of fiber-depleted solid food exits more quickly. In a study entitled “Gastric Emptying of a Solid Meal Is Accelerated by the Removal of Dietary Fibre Naturally Present in Food,” researchers compared how long it took for a meal that included higher-fiber foods—whole-wheat pasta with puréed fruits and vegetables—to leave the stomach compared to a meal with the same volume and same calories, but made from white pasta and fruit and vegetable juices. The fiber-depleted meal was out of the stomach forty-five minutes earlier than the meal with the fiber intact.1192

Written by LeisureGuy

19 January 2020 at 4:31 pm

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