Stealth
Forces in Weight loss
The field
of weight loss is like the ancient fable about the blind men and the
elephant Each man investigates a different part of the animal and reports
back, only to discover their findings are bafflingly incompatible.
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A
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The various
findings by public-health experts, physicians, psychologists, geneticists,
molecular biologists, and nutritionists are about as similar as an
elephant’s tusk is to its tail Some say obesity is largely predetermined by
our genes and biology; others attribute it to an overabundance of fries,
soda, and screen-sucking; still others think we’re fat because of viral
infection, insulin, or the metabolic conditions we encountered in the womb.
“Everyone subscribes to their own little theory/’ says Robert Berkowitz,
medical director of the Center for Weight and Eating Disorders at the
University of Pennsylvania School of Medicine. We’re programmed to hang
onto the fat we have, and some people are predisposed to create and carry
more fat than others. Diet and exercise help, but in the end the solution
will inevitably be more complicated than pushing away the plate and going
for a walk. “It’s not as simple as ‘You’re fat because you’re lazy:” says
Nikhil Dhurandhar, an associate professor at Pennington Biomedical Research
Center in Baton Rouge. “Willpower is not a prerogative of thin people. It’s
distributed equally.”
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B
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Science may
still be years away from giving us a miracle formula for fat-loss. Hormone
leptin is a crucial player in the brain’s weight-management circuitry. Some
people produce too little leptin; others become desensitized to it. And
when obese people lose weight, their leptin levels plummet along with their
metabolism. The body becomes more efficient at using fuel and conserving
fat, which makes it tough to keep the weight off. Obese dieters’ bodies go
into a state of chronic hunger, a feeling Rudolph Leibel, an obesity
researcher at Columbia University, compares to thirst. “Some people might
be able to tolerate chronic thirst, but the majority couldn’t stand it/’
says Leibel “Is that a behavioral problem—a lack of willpower? I don’t
think so.”
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C
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The
government has bng espoused moderate daily exercise—of the evening-walk or
take-the-stairs variety – but that may not do much to budge the needle on
the scale. A 150-pound person burns only 150 calories on a half-hour walk,
the equivalent of two apples. It’s good for the heart, less so for the gut.
“Radical changes are necessary/’ says Deirdre Barrett, a psychologist at
Harvard Medical School and author of Waistland.”People don’t bse weight by
choosing the small fries or taking a little walk every other day.” Barrett
suggests taking a cue from the members of the National Weight Control Registry
(NWCR), a self-selected group of more than 5,000 successful weight-losers
who have shed an average of 66 pounds and kept it off 5.5 years. Some
registry members lost weight using low-carb diets; some went low-fat others
eliminated refined foods. Some did it on their own; others relied on
counseling. That said, not everyone can lose 66 pounds and not everyone
needs to. The goal shouldn’t be getting thin, but getting healthy. It’s
enough to whittle your weight down the low end of your set range, says Jeffrey
Friedman, a geneticist at Rockefeller University. Losing even 10 pounds
vastly decreases your risk of diabetes, heart disease, and high blood
pressure. The point is to not give up just because you don’t look like a
swimsuit model
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D
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The
negotiation between your genes and the environment begins on day one. Your
optimal weight, writ by genes, appears to get edited early on by conditions
even before birth, inside the womb. If a woman has high blood-sugar levels
while she’s pregnant, her children are more likely to be overweight or
obese, according to a study of almost 10,000 mother-child pairs. Maternal
diabetes may influence a child’s obesity risk through a process called
metabolic imprinting, says Teresa Hillier, an endocrinologist with Kaiser
Permanente’s Center for Health Research and the study’s lead author. The
implication is clear: Weight may be established very early on, and obesity
largely passed from mother to child. Numerous studies in both animals and
humans have shown that a mother’s obesity directly increases her child’s
risk for weight gain. The best advice for moms-to-be: Get fit before you
get pregnant. You’ll reduce your risk of complications during pregnancy and
increase your chances of having a normal-weight child
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E
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It’s the
$64,000 question:Which diets
work? It got people wondering: Isn’t there a better way to diet? A study
seemed to offer an answer. The paper compared two groups of adults: those
who, after eating, secreted high levels of insulin, a hormone that sweeps
blood sugar out of the bloodstream and promotes its storage as fat, and
those who secreted less. Within each group, half were put on a low-fat diet
and half on a tow-glycemic-bad diet. On average, the tow-insulin-secreting
group fared the same on both diets, losing nearly 10 pounds in the first
six months — but they gained about half of it back by the end of the
18-month study. The high-insulin group didn’t do as well on the low-fat
plan, losing about 4.5 pounds, and gaining back more than half by the end
But the most successful were the high- insulin-secretors on the
low-glycemic-bad diet. They lost nearly 13 pounds and kept it off.
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F
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What if your
fat is caused not by diet or genes, but by germs一say, a virus?
It sounds like a sci-fi horror movie, but research suggests some dimension
of the obesity epidemic may be attributable to infection by common viruses,
says Dhurandhar. The idea of “infectobesity”
came to him 20 years ago when he was a young doctor treating obesity in
Bombay. He discovered that a local avian virus, SMAM-1, caused chickens to
die, sickened with organ damage but also, strangely, with lots of abdominal
fat. In experiments, Dhurandhar found that SMAM-l-infected chickens became
obese on the same diet as uninfected ones, which stayed svelte.
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G
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He later
moved to the U.S. and onto a bona fide human virus, adenovirus 36 (AD-36).
In the lab, every species of animal Dhurandhar infected with the virus
became obese_chickens got fat, mice got fat, even rhesus monkeys at the zoo
that picked up the virus from the environment suddenly gained 15 percent of
their body weight upon exposure. In his latest studies, Dhurandhar has isolated
a gene that, when blocked from expressing itself, seems to turn off the
virus’s fattening power. Stem cells extracted from fat cells and then
exposed to AD-36 reliably blossom into fat cells – but when stem cells are
exposed to an AD-36 virus with the key gene inhibited, the stems cells
don*t differentiate. The gene appears to be necessary and sufficient to
trigger AD-36-related obesity, and the goal is to use the research to
create a sort of obesity vaccine.
Researchers
have discovered 10 microbes so far that trigger obesity – seven of them
viruses. It may be a long shot, but for people struggling desperately to be
thin, even the possibility of an alternative cause of obesity offers some
solace. “They feel better knowing there may be something beyond them that
could be responsible,” says Dhurandhar. “The thought that there could be
something besides what they’ve heard all their lives – that they are greedy
and lazy – helps.”
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Questions 14-18
Reading Passage 2 has five sections,
A-G.
Which section contains the following
information? Write the correct letter, A-G, in boxes 14-18 on your answer
sheet.
14
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evaluation on the effect of weight loss on different kind of diets
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15
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an example of research which include relatives of participants
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16
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Example of
a group of people who never regain weight immediately after.
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17
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long term hunger may appear to be acceptable to most of the
participants while losing weight
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18
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a
continuous experiment may lead to a practical application besides diet or
hereditary resort.
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Questions 19-23
Look at the following researchers and
the list of findings below. Match each researcher with the correct finding.
Write the correct letter in boxes 19-23
on your answer sheet.
List of Researchers
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A
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Robert
Berkowitz
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B
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Rudolph
Leibel
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C
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Nikhil
Dhurandhar
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D
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Deirdre
Barrett
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E
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Jeffrey
Friedman
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F
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Teresa
Hillier
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19
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A person’s weight is predetermined to a set point by the DNA.
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20
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Pregnant mother who are overweight may risk their fetus
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21
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The aim of
losing Wright should be keeping healthy rather than attractiveness
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22
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mall changes in lifestyle will not have great impact on reducing
much weight
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23
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Researchers
should be divided into different groups with their own point of view about
weight loss.
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Question 24 – 27
Complete the summery below.
Choose NO MORE THAN ONE WORD from the
passage for each answer. Write your answers in boxes 24-27 on your answer
sheet.
In Bombay Clinic, a young doctor who came up with the concept ‘infect
obesity1 believed that the obesity is caused by a kind of virus, Years of
experiment that he conducted on 24 ……………………… Later he moved to America and
tested on a new virus named 25……………………… which proved to be a significant
breakthrough. Although there seems no way to eliminate the virus, a kind of
26……………………… can be separated as to block the expressing power of the virus.
The doctor future is aiming at developing a new 27………………… to effectively
combating the virus.
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