首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Your weight affects how long you live—but it’s extremely complicated A) We often think about weight loss in the short term, h
Your weight affects how long you live—but it’s extremely complicated A) We often think about weight loss in the short term, h
admin
2019-04-30
33
问题
Your weight affects how long you live—but it’s extremely complicated
A) We often think about weight loss in the short term, hoping to drop 5 pounds in time for vacation or 10 in time for a wedding. Of course, this kind of yo-yo dieting isn’t the greatest for our health. If you’re going to ask how much you should weigh, you want to think long term—what weight will keep you healthy?
B) This question has been at the forefront of researchers’ minds for a while, and for good reason. Global obesity rates are high and steadily increasing, with 1.3 billion adults considered overweight and 600 million in the weight range categorized as obese.
C) While it’s true that muscle weighs more than fat, most people who are carrying around a few extra pounds are doing so in the form of adipose (脂肪的) tissue. Unlike bone and muscle, fat cells can generate inflammation (炎症), allowing us to heal infections and protect our bodies from further damage. But having too many fat cells causes our bodies to release inflammatory proteins all the time. Many studies indicate this can increase our risk of developing cancer.
D) Carrying around extra fat cells also affects other physiological pathways, many of which—high blood pressure, hyperglycemia (高血糖症) , and high cholesterol, for example—can lead to potentially fatal heart problems.
E) We all need some amount of body fat. So how much is too much? Using BMI (body mass index, the body mass divided by the square of the body height) and rates of overall mortality, scientists studying this question initially came to a surprising conclusion: On a population level, the relationship between BMI and mortality formed a U-shaped curve, in which the lowest point (the one where mortality was at its lowest) was actually at a BMI range considered nearly overweight (about 24.5, when 25 is overweight). Bring on all the healthy fats and carbs (含碳水化合物的食物).
F) But some scientists—including Andrew Stokes, a chronic disease and global health researcher at Boston University—challenged those conclusions. Instead of a U-shaped curve, his group’s follow-up studies saw the risk of mortality increase with higher BMIs. The lowest risk category, he says, is somewhere in the low-normal weight range, and risk increases pretty consistently as BMI goes up.
G) The earlier studies failed to account for two important factors, according to Stokes. "The normal weight category used in most of the studies combines low-risk, stable weight people with high-risk individuals who have lost weight," he says. If a study subject spends most of his life obese and then loses weight, he might accumulate years of negative health effects. Not all of those risks disappear with weight loss. "Much of the research on obesity just uses a snapshot (简要描述) of weight currently," says Stokes.
H) Stokes equates this to the way we study smoking. You can’t simply compare non-smokers to smokers. Non-smokers include those who have never smoked as well as those who may have smoked for several decades and then quit.
I) And smoking itself is another crucial factor in these BMI studies, Stokes says. Smoking can present a huge bias in estimating risks associated with obesity, because the habit affects body weight through metabolic effects and reduced appetite. By failing to take smoking into account, your analysis may include people who have a low body weight but smoke heavily, upping their chance of an early death. Once those outliers are removed, Stokes and his colleagues argue, the relationship between excess body weight and early mortality is clear.
J) Of course, the range for normal BMI is pretty broad. For example, someone who is 5’4" has a normal BMI if they weigh anywhere from 108 pounds to 145 pounds. If we want to know which sliver of the range is actually best, Stokes says, researchers have a lot more work to do.
K) And then there’s the question of whether BMI is the right metric to use at all. BMI is often criticized as a poor indicator of health. Because muscle weighs more than fat, a weightlifter could have a BMI in the overweight range, and that’s to say nothing of all the other variations the human form can take. Even two folks with the same BMI and the same amount of actual body fat might face different risks due to their adipose, if one carries more in their belly and the other stores more in their hips. Studies that compare BMI to superior methods like the Dexa scan, a type of X-ray that can determine exactly how much body fat you have and where, show that the potential misclassification is not trivial. But Stokes argues that on a population level, BMI is a pretty good parameter to use. Variations in its accuracy do exist, but it’s not so wildly off-base as to be useless when we make generalizations about risks throughout an entire population.
L) But that’s the key here: We’re talking about average risk. None of this is to say that someone with an ideal BMI is bound to outlive someone who is obese. There are plenty of other factors at play in determining our health, including genetics, exercise, diet, and especially stress. The degree of fat we carry often intertwines with these other characteristics, but it’s still only one factor. An individual’s health can’t be determined by a number on a scale, and one should always talk to a doctor when considering major lifestyle changes.
M) Still, while there’s no scientific consensus on what range of normal BMI equates to lowest overall mortality, Stokes hazards a guess for the lower end, perhaps 20 to 22. He also points out that many studies (on rodents and primates, anyway) show calorie restriction can increase longevity. One population he thinks we should study more are those humans who have always had a very low BMI. Ping-ponging your weight around to try to get on the lowest possible end of the healthy threshold is definitely not a good idea, but living your entire life with a BMI on the lower end—maybe even under 20—could decrease risk of diseases like cancer and diabetes. It’s an important question, Stokes says, and one that not enough researchers are asking.
Researchers have to make more efforts to identify the best range for BMI.
选项
答案
J
解析
转载请注明原文地址:https://jikaoti.com/ti/SyKFFFFM
0
大学英语六级
相关试题推荐
Articlesinmagazinesandnewspapersandspecialreportsonradioandtelevision【B1】______theconcernofmanyAmericansaboutth
JuanLouis,ajuniorgeologymajor,decidedtogivean【B1】______speechabouthowearthquakesoccur.Fromhisaudienceandanalys
A、Peopletendtounderestimatetheirmentalpowers.B、Mostpeoplehavearatherpoorlong-termmemory.C、Peoplecanenhancethei
人民币(RenminbiorRMB)是中国大陆地区的法定货币。中国人民银行(thePeople’sBankofChina)是国家管理人民币的主要机构,负责人民币的设计、印制和发行。从1948年开始,人民币一共发行了五套。目前市场上流通的主要是第
A、Sheisworriedshecan’tattendthecourse.B、Sheisworriedshehastochangeprofessor.C、Sheisworriedshemightnotbeab
Fertilizerusehasexploded,overloadingplantsworldwide,likelyalteringecosystemsfordecadestocenturies,scientistsrepor
A、Whetheritisnecessarytoputlabelsonpreparedfoods.B、Whatingredientshouldanutritionlabellist.C、Howtogetconsume
A、Awatercurrentstruckhisshipviolently.B、Awavecarriedhisshipfaraway.C、Greatnoisecamedownfromthesky.D、Roughs
Somethingveryunusualhappenedabout80,000yearsago,asEarth’slasticeagewasgettingstarted.Sealevelsthathadbeendr
A、Thosewholiveinthevirtualworld.B、Thosewhohavetoworklonghours.C、Thosewhoareusedtoonlinetransactions.D、Those
随机试题
患者伤后由烦躁进入昏迷,并出现后一侧瞳孔散大,光反射消失,多见于患者伤后双侧瞳孔不等大,时大时小,伴意识障碍,多见于
甲企业向乙银行借款100万元,以企业现有的以及将有的生产设备、原材料、半成品、产品设定抵押担保,双方签订了书面抵押协议,并到工商行政管理部门办理了抵押登记。借款期限届至,甲企业无力还款,乙银行准备行使抵押权。经查,甲企业仅有的一套设备已经出卖给丙公司,双方
注册建筑师的执业范围,主要包括()。
根据《建设工程工程量清单计价规范》,关于装饰装修工程量计算的说法,正确的是()。[2012年真题]
在工程预付款数额的计算公式中,年度施工天数通常按()计算。
下列做法中,不符合《建筑法》关于承揽工程的规定的是()
某承包商在混凝土重力坝施工过程中,采用分缝分块常规混凝土浇筑方法。由于工期紧,浇筑过程中气温较高,为保证混凝土浇筑质量,承包商积极采取了降低混凝土的入仓温度等措施。在某分部工程施工过程中,发现某一单元工程混凝土强度严重不足,承包商及时组织人员全部
20世纪80年代以来,国际金融市场最重要的创新便是金融衍生品市场的发展。最早出现的是简单的衍生品,如远期、期货、期权、互换等,随后出现了多种复杂产品。20世纪90年代信用衍生品的出现,将金融衍生品市场的发展推向新的阶段。在2007年爆发的美国次贷危机中,信
科技进步是推动经济全球化的()。
带领30人的旅游团在北京游览时,地陪应事先准备好并携带()
最新回复
(
0
)