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Blends historical perspectives with cutting-edge research to examine body fat as a critical endocrine organ that can be better understood and managed when recognized as a necessary component of human health.
Biochemist Sylvia Tara explores the surprising science behind our most hated body part. Fat is an obsession, a dirty word, a subject of national handwringingand, according to biochemist Sylvia Tara, the least-understood part of our body. You may not love your fat, but your body certainly does. In fact, your body is actually endowed with many self-defense measures to hold on to fat. For example, fat can use stem cells to regenerate; increase our appetite if it feels threatened; and use bacteria, genetics, and viruses to expand itself. The secret to losing twenty pounds? You have to work with your fat, not against it. Tara explains how your fat influences your appetite and willpower, how it defends itself when attacked, and why it grows back so quickly. The Secret Life of Fat brings cutting-edge research together with historical perspectives to reveal fat's true identity: an endocrine organ that, in the right amount, is critical to our health. Fat triggers puberty, enables our reproductive and immune systems, and even affects brain size. Although we spend $60 billion annually fighting fat, our efforts are often misinformed and misdirected. Tara expertly illustrates the complex role that genetics, hormones, diet, exercise, and history play in our weight, and The Secret Life of Fat sets you on the path to beat the bulge once and for all.--Dust jacket.… (altro)
The book contains lots of science about fat with stories about people that make it very interesting to read. It is easily understood with special terms defined and explained. I found it an engaging read, even a sort of page-turner. We learn a lot about types of body fat, what fat does for us, and how fat tends to protect itself. With the science in mind we get ideas of how we might make our own plan for dealing with excess fat. The book shows us how this can be a monumental task leading to a better understanding of the problem much as we have learned to look at the problem of diabetes. We may be able to look at ourselves and others who are overweight less negatively as a result of reading this book and understanding more about what actually can lead to the condition.
The book gives a lot of information. It does not offer us a diet plan. The author does share specifically what she does, but tells us that we are all different in what we need. We can take the information and use what meets our own needs. ( )
The title couldn’t be more perfect. Fat is a universe unto itself, and we are only now discovering how it runs our bodies. The book is as dramatic as the title, and the chapters are filled with case studies of individuals and research findings, and both from all over the world. It is also very personal, inspired by Tara’s own combat with fat. Informed by her own findings, she beats her fat at its own game.
Tara has a lovely description of fat: glucose is like cash, glycogen (chains of glucose) like a checking account, and fat is a certificate of deposit. There are three kinds of fat – white, beige and brown. White is the classic, energy store. Beige waits for signals to change to brown, which is saturated with mitochondria and burns energy instead of storing it. This, for obvious reasons, has become an obsession for research.
-Like any other organ, fat will fight for life. Constant diet changing, losing and regaining a few pounds, only makes it tougher. It has the communication and receptor tools to keep itself in control. It manipulates the brain and participates in brain signals. -Fat signals the body for angiogenesis – it orders up new veins and arteries to approach it, in order to feed it, just like a tumor. -Fat knows when there is too much of it and signals the body to manufacture cytokines – inflammatories – the usual first line of defense. -Fat is an endocrine organ – it produces hormones (leptin) that latch onto the brain’s hypothalamus and tell it to be hungry – or not. -By reducing leptin levels, remaining fat makes people feel hungrier than they were before reducing. -Fat circulates adiponectin which helps clear the blood - of fat. Those with high levels can be very fat and perfectly healthy. Hard exercise increases levels. -More than 50% of cells in the fat of the obese are immune cells, vs 5% in the fat of the normal or thin. -Fat resurges by lowering energy levels, so dieters have to work harder than normal to keep weight off. Only consistent, hard exercise overcomes the return of fat - even following liposuction. -Half a pound of fat can contain 50 million stem cells, used to rebuild muscle, bone and organs throughout the body. Doctors are quickly learning to repurpose them.
-Hard exercise overcomes genetic predispositions to fat and weight in most cases.
Chapter 8 is all about how women’s bodies deal differently with fat. Their fat is a better kind (subcutaneous vs visceral), but there is more of it, and it takes them disproportionately more effort in the gym and less at the table to achieve the goals men see more easily.
There is a fascinating analysis of sumo wrestlers, those hugely fat men whose sole job in life is to push other obese opponents out of the ring. The surprise is their blood levels are excellent, and they are extraordinarily healthy – as long as they keep to the training regimen and diet. Once they retire, they quickly slide into fat hell.
Oddly, the chapter I was expecting – how do people with no fat and extreme, reduced calorie diets – fare – is missing. In animal studies, such diets extend lifespans and energy levels dramatically. So is fat really necessary, or are we better off without it altogether? No mention in The Secret Life of Fat.
Tara’s book is a lovely combination of the emotional and the scientific, the personal and the universal, narrative and science. It is lean and muscled and terrifically readable.
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Dedicated to my parents
Incipit
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It was a breezy Friday evening in the fall in San Diego.
Citazioni
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We spend billions in the war against fat—chemical weapons, surgical devices, behavior restructuring, exercise contraptions, and rationed food programs—but despite our best efforts, fat returns. Clearly, we do not understand the enemy we're fighting.
And maybe as we start to understand our "enemy" we'll realize that it is not all bad. New research is showing us that fat secretes essential hormones, enables many bodily functions, keeps us safe from disease, and may even help us live longer. Fat appears to be so important that our stem cells are capable of creating it independent of our food intact—a function that has been observed for critical tissues such as muscle, bone, and brain.
But thousands of research studies from around the world are now revealing that fat is not just fat—it is a dynamic and interactive endocrine organ that has life-or-death influence over us. It is so important that nature ensures we have it beginning in the womb. At about fourteen weeks of gestation, the embryo starts to manufacture fat, even before all systems are functioning. As later chapters describe, fat controls our appetite, influences our emotions, supplies energy, and enables the activities of other body parts.
Fat cells (also called adipocytes) could expand their volume more than one thousand times normal size by pushing other cell contents off to the side.
Shapiro and Wertheimer had discovered that fat possessed the power to produce itself.
If you want to understand the way our bodies use that energy, think of money. Just as currency is used for every exchange in our economy, energy is needed for every transaction in our bodies. Money exists in different forms: cash, checking accounts, and long-term savings accounts. Sometimes, we need cash to spend right away. Other times we just want it nearby and ready for use. And some we save for that rainy day. In the body, glucose is cash, glycogen is a checking account , and fat is a certificate of deposit.
Unlike glycogen, fat is not simply glucose stacked away and available for use. Fat molecules (also called fatty acids) are chains of fourteen to twenty carbon atoms that are linked together. These molecules are joined in threes to form triglycerides, which are long, lithe, and malleable so they can be packed tightly together in our fat cells. When the body is low on glucose and glycogen, it reaches for fat and converts it into the energy it needs. Fat is the certificate of deposit not easy to get to, but it can safely hold a lot of energy in reserve.
From the liver, fat molecules travel in the bloodstream and are deposited in our body cells, most obviously into our fat cells. Fat molecules repel water and pack together so efficiently that 40,000 calories weighs just ten pounds in our bodies. If we had to store the same amount of energy in glycogen or glucose, with water mixed in, we would weigh more than twice as much as we do.
You may be surprised to know that our active brains use as much energy as our muscles. The liver is a close second to the brain, with the heart, gastrointestinal system, and kidneys coming in close behind.
One way to imagine chromosomes and genes is to think of them as books in a library. The DNA is the library, the chromosomes are the bookshelves, and genes are the books, with each book holding the instructions for how to code a protein that has a function in our body.
By producing a protein that was linked to appetite, fat revealed itself to be a clever, interactive organ that could control its own destiny.
Through leptin, fat could talk. It could tell the brain to stop eating. And by refusing to deliver the message, fat could induce us to eat more.
Frisch determined that there was a minimum requirement of 17 percent body fat in order for menstruation to begin at puberty, but 22 percent body fat was needed to continue regular menstruation as girls approached the age of sixteen.
The subcutaneous fat (fat directly under the skin) in a woman's body can convert male hormones, called androgens, into estrogen. Fat makes this conversion by means of an enzyme called aromatase. Young women make estrogen both in their ovaries and in their fat. (The latter is the primary source of the hormone in postmenopausal women.)
But leptin also caused a leap in their psychological maturity. Before treatment, this pair acted more childlike and docile. But after only two weeks of leptin injections, before any significant weight loss, their behavior changed to be more adult and assertive.
The stem cell that eventually becomes a fat cell is also capable of turning into a bone cell. Fat and bone are like twins that come from the same birthplace. As such, they have a unique relationship to one another. They can even turn into one another when prompted
A study by Kaiser Permanente in California in 2008 followed 6,538 people for three decades. Those who had the most belly fat between the ages of forty and forty-five were almost three times more likely to have dementia in their seventies than those who were normal weight. Another study done by researchers of the Framingham Heart Study and other institutions showed that brain volume is affected too.
The right amount of fat in the right place helps maintain our brains.
Evidently, the sumo's physical exercise and diet low in sugar helps him to avoid visceral fat.
Exercise has been shown to increase adiponectin levels, and vigorous exercise, such as jogging twenty miles per week, or high-intensity training for three days or more per week reduces visceral fat. It is thought that the intense physical regimen of the sumo is what enables their fat to be stored in the periphery instead of in the visceral area. And when the sumo curtails this exercise regimen, unhealthy visceral fat quickly accumulates.
"In our program we have seen that just a 7 percent weight loss can improve insulin sensitivity by 57 percent."
Through its most powerful messenger, leptin, fat can influence our appetites. It can cause our muscles to reduce their energy usage. It can alter our sympathetic nervous system, and control the flow of hormones such as thyroid, adrenaline, and noradrenaline. Most profoundly, it can influence our thoughts and elicit stronger responses to food, lower our inhibition to eating, and cause us to misjudge how much we've eaten. Fat, it turns out, is capable of mind control!
Proietto realized the discouraging truth: combined changes in hormones were working together to make successful dieters crave food much more after they lost weight than before, inducing them to regain lost pounds.
As fat becomes enlarged from overeating, it reacts by releasing the same chemical signals that go to nearby veins, causing them to sprout in the direction of the fat. This creates additional blood supply, which delivers nutrients and oxygen that enable the fat to thrive and ultimately produce new fat cells. These newly formed blood vessels also create additional paths for circulating triglycerides to be deposited into fat tissue. Indeed, fat begets fat.
Survival skills. Mind control. Reprogramming. Jason Bourne? No, it's your fat.
The increased exposure to the environment in our first few years of life increases the types and numbers of bacteria we have, and as we grow our guts come to possess around 100 trillion microbes. Ultimately, humans have ten times more one-celled microbes in our bodies than our own body cells, meaning we are actually more microbial than human.
Bouchard found that our genes influence our resting metabolism, fat mass, percent of fat, and abdominal visceral fat, plasma triglyceride, and cholesterol levels.
The lesson is clear: once we enter a specific range of strenuous exercise, the body kicks in to lose fat no matter what our genes want.
But in people with the FTO mutation, there are fewer cells turning into beige cells and more turning into energy-storing white cells. So the result of the FTO mutations is a drive to eat higher-calorie foods paired with less calorie burning, and more calorie hoarding. A challenging combination for any dieter.
But the IRS1 was the first that was linked specifically to fat cell creation. When we don't create new fat cells to house our circulating fats, we are prone to more diseases. With less fat, we may appear to be healthier, but may actually be in danger of developing diabetes and other diseases.
In the end, daily actions matter more. How much we decide to eat, what we eat, and how much we choose to exercise will, in the majority of cases, trump our genes.
The effects of sex hormones on fat are so powerful that when men are given estrogen, as in the case of transsexuals, they gain body fat overall, even though their caloric intake is the same as before. Not only do they gain fat but they gain it disproportionately in the same places as women—the thighs and buttocks.
Babies have more brown fat, percentage-wise, than any other age group.
As we age, our fat mass peaks. Between fifty and sixty, we are typically at our heaviest and have the most difficult time keeping fat in check.
In the decades to come, it was discovered that fat has receptors for our most potent hormones—thyroid hormone, growth hormone, estrogen, testosterone, and progesterone. All these hormones tell fat when it is time to liquidate and release energy into the system.
When we are young, we have an abundance of these hormones. They work to grow our tissues, activate our reproductive systems, and keep our energy and metabolism high, which helps young people lose weight faster and keep it off more easily. But when we approach middle age we no longer need to activate our reproductive systems. Biologically speaking, we've outlived our usefulness. At this point, the production of most of those hormones decreases, which means the messages to our fat to dissolve itself are less powerful. With our bodies burning less adipose tissue through hormonal messaging, we inevitably get fatter.
Testosterone is important for everyone's weight management because it helps build and maintain muscle mass. It also burns fat and increases energy. As testosterone declines with age, the result is a loss of lean mass and muscle tone, lower mental energy and more visceral fat. When lean mass and muscle tone go, metabolism slows even further, since muscle burns more calories than fat does.
The relationship between fat and testosterone in men is circular—lower testosterone leads to an increase in fat, particularly belly fat; in turn, higher fat lowers testosterone. It is a downward cycle in which fat begets fat.
"When I took the testosterone booster, I was thinking, 'Oh, my God, I'm looking good. I'm feeling great. I'm working out. I'm feeling sexy.' And then some days I'd wake up and look in the mirror and say, 'Oh, my God, I'm looking fat.' I finally tied that experience to when I was due to take the estrogen blocker. Too much estrogen made me think I was fat. And I finally realized what my ex-wife and girlfriend go through when they say 'I'm feeling fat today.' It's like, wow! It's the estrogen, literally!" Mike was discovering that hormones affect our attitudes—how we view ourselves, and how we view others.
One of the natural ways to activate hormones is exercise. If we can overcome the sluggish feeling that weight gain causes and exercise at least three times per week for forty-five minutes, we can increase secretion of some hormones.
Exercise also increases adiponectin, the hormone emitted by fat tissue that moves fat away from visceral to the limbs and hips. It improves insulin sensitivity, too, leading to lower blood glucose and triglyceride levels. The added benefit of most of these hormones is that they won't just burn fat, they'll increase lean tissue, which also leads to higher metabolism. So even at rest, we'll burn more calories.
"I recommend walking an hour each day to burn extra calories without increasing appetite, with moderate weight training two to three times per week to increase lean muscle mass."
What we eat and how much also affects our hormone levels. Our growth-hormone levels are naturally reduced by sugars and fats.
Not eating anything also increases our levels of fat-burning hormones. Many body builders and work-out enthusiasts swear by intermittent fasting. When blood sugar becomes low, it triggers the release of fat-burning hormones including adrenaline and growth hormone. Growth-hormone release peaks at night and during sleep.
Moreover, the fat we gain in middle age isn't permanent. Surprisingly, once we reach our seventies, fat seems to go into reverse and we start to lose it. With age, fat cells shrink—they are no longer capable of holding as much fat.
Eating about ten grams of protein after mild exercise, or twenty grams after more strenuous workouts, helps control hunger, as will adding plenty of fiber to one's diet.
A common suggestion by trainers is a sixteen-hour daily fast (including sleep time) for women and a fourteen-hour fast for men.
If we are sedentary, fat will accumulate in areas near our internal organs and hurt us; exercise helps direct fat to the subcutaneous layer.
self-control can be strengthened, much like a muscle.
Milkman's work operates on the premise that we each have two selves—one that is controlled, thoughtful, and focused on the future, which she calls the "should" self, and a separate one in competition, the impulsive "want" self.
"When we make a choice for the present, people tend to choose what they want. When we make a decision about tomorrow, we choose what we should do."
Repeatedly exercising a "should" activity strengthens the part of the brain responsible for self-control. This finding supports Muraven's conclusion that practicing small acts of willpower increased subjects' ability to take on bigger tasks involving self-control.
If we pair an unappealing chore with something we like to do, we increase the odds that we'll perform the challenging task.
if you repeat the behavior that you want to incorporate, it will eventually become a habit.
Ultime parole
Dati dalle informazioni generali inglesi.Modifica per tradurlo nella tua lingua.
And our efforts to manage it will be up to par with the amazing scientific research revealing its potential.
Blends historical perspectives with cutting-edge research to examine body fat as a critical endocrine organ that can be better understood and managed when recognized as a necessary component of human health.
Biochemist Sylvia Tara explores the surprising science behind our most hated body part. Fat is an obsession, a dirty word, a subject of national handwringingand, according to biochemist Sylvia Tara, the least-understood part of our body. You may not love your fat, but your body certainly does. In fact, your body is actually endowed with many self-defense measures to hold on to fat. For example, fat can use stem cells to regenerate; increase our appetite if it feels threatened; and use bacteria, genetics, and viruses to expand itself. The secret to losing twenty pounds? You have to work with your fat, not against it. Tara explains how your fat influences your appetite and willpower, how it defends itself when attacked, and why it grows back so quickly. The Secret Life of Fat brings cutting-edge research together with historical perspectives to reveal fat's true identity: an endocrine organ that, in the right amount, is critical to our health. Fat triggers puberty, enables our reproductive and immune systems, and even affects brain size. Although we spend $60 billion annually fighting fat, our efforts are often misinformed and misdirected. Tara expertly illustrates the complex role that genetics, hormones, diet, exercise, and history play in our weight, and The Secret Life of Fat sets you on the path to beat the bulge once and for all.--Dust jacket.
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The book gives a lot of information. It does not offer us a diet plan. The author does share specifically what she does, but tells us that we are all different in what we need. We can take the information and use what meets our own needs. (