Weight Management- Are You at a Healthy Weight? Your first step to find out if you are at a healthy weight is to find out what your BMI, or body mass index, is and what your waist size is. For most people, these are good clues to whether they are at a healthy weight. What's your BMI? A healthy weight is one that is right for your body type and height and is based on your body mass index (BMI) and the size of your waist (waist circumference). If you are age 2. Interactive Tool: Is Your BMI Increasing Your Health Risks? Talk to your doctor to find out if your weight is a symptom of a medical problem. A registered dietitian can help you learn about healthy eating. If your BMI is between 1. But your health may still be at risk if you are not getting regular physical activity and practicing healthy eating. If your BMI is 2. This may or may not be unhealthy, depending on some other things, like your waist size and other health problems you may have. If your BMI is 3. You may need to lose weight and change your eating and activity habits to get healthy and stay healthy. See the topic Obesity. Dieting seems to be a way of life for many Americans. In 2011, 75 million weight-loss seekers spent over $60 billion trying to fight the battle of the bulge.![]() If you are Asian, your recommended weight range may be lower. It's important to remember that your BMI is only one measure of your health. A person who is not at a . People who are thin but don't exercise or eat nutritious foods aren't necessarily healthy just because they are thin. ![]() Continued. What's your waist size? After you know your BMI, it's time to look at your waist size. Measuring your waist can help you find out how much fat you have stored around your belly. Diseases that are related to weight include type 2 diabetes, heart disease, and high blood pressure. ![]() No one number of calories per kilogram is appropriate for everyone; a number of. Measure your waist size with a tape measure. The tape should fit snugly but not press into your skin. For most people, the goal for a healthy waist is: 1 Less than 4. If you are Asian, the goal for a healthy waist is: Less than 3. You may need to change your eating habits and get more active. In the overweight category on the BMI chart but your waist size is within the recommendations: Your weight may be right for you. But you need to see your doctor to find out if you have health problems that might be related to your weight. In the obese category on the BMI chart, no matter what your waist measurement is: You may need to lose weight to be healthier, as well as change your eating and activity habits. This measurement is a comparison of your waist size to your hip size. A higher waist- to- hip ratio means that you are more . Continued. Do you have other health problems? ![]() If you are in the overweight or obese category and your waist size is too high, it's important to talk to your doctor about weight- related health problems you may have, including: If you have two or more of these health problems, your doctor may advise you to make some lifestyle changes and/or lose weight. He or she may also refer you to a dietitian, an expert in healthy eating. Interactive Tool: Is Your Weight Affecting Your Health Risks? Are you unhappy with your weight? If you're at a healthy weight but are still unhappy with your weight, you're not alone. Lots of people are. ![]() ![]() It can be hard to be satisfied with how you look when TV and magazines show unrealistic images of what it means to be thin. Here are some things to think about: There is no . We let society tell us what . But the way a skinny model looks in a magazine or TV ad is not normal or ? Can you do the activities you want to do? That's what healthy living is all about, no matter what your weight is. ![]() Trying to lose weight when you don't have to can actually be bad for you. Most people who diet end up gaining back the pounds they lost- and more. Web. MD Medical Reference from Healthwise. This information is not intended to replace the advice of a doctor. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated. ![]() This Kilogram Has A Weight- Loss Problem : NPRMore than a century ago, a small metal cylinder was forged in London and sent to a leafy suburb of Paris. The cylinder was about the size of a salt shaker and made of an alloy of platinum and iridium, an advanced material at the time. Then, by international treaty, they declared it to be the international standard. Since 1. 88. 9, the year the Eiffel Tower opened, that cylinder has been the standard against which every other kilogram on the planet has been judged. But that's creating problems. According to scientists, the cylinder's mass appears to be changing. The solution is a new kilogram, one that is based on a constant number instead of a physical object. To get that number, scientists have had to build a special kind of scale, one that measures the kilogram without balancing it against another mass. It has been a long, slow process, but today they are close to redefining the kilogram once and for all. Please Don't Sneeze On The Kilogram.
As it stands, the entire world's system of measurement hinges on the cylinder. If it is dropped, scratched or otherwise defaced, it would cause a global problem. If somebody sneezed on that kilogram standard, all the weights in the world would be instantly wrong. Richard Steiner. For that reason, the official kilogram is kept locked inside a secured vault at the International Bureau of Weights and Measures near Paris. Scientists are so paranoid that they've only taken it out on three occasions: in 1. Each time, they've compared it to a set of copies. In 1. 88. 9, the copies and the kilogram weighed the same, but by 1. Based on the data, the kilogram appears to weigh slightly less than the copies. The real crux of this problem is that it's impossible to tell what has changed over the past 1. The copies may have grown heavier over time by absorbing air molecules. But it's equally possible that the kilogram is getting lighter. Periodic washings, for example, may have removed microscopic quantities of metal from its surface. Or it could be that both the copies and the kilogram are changing, but at different rates. ![]() There is no way to tell what's happening because mass is always calibrated against another mass, says Peter Mohr, a theoretical physicist at NIST who is working on the kilogram problem. The good news is that the change is extremely small, around 5. Constants are used by physicists to describe the natural world. They are both precise and unchanging . Scientists have already used constants to redefine other units of measurement, like the meter. Originally the meter was equal to the length of a piece of metal kept alongside the kilogram, but in 1. Because the speed of light is constant, this new definition means that the meter will never change. Fixing the kilogram is more complicated. Scientists would like to express it in terms of a fundamental constant called Planck's constant. Planck's constant is a vanishingly small number used in atomic- scale quantum mechanical calculations. This extremely sensitive scale can detect changes as small as ten- billionths of a kilogram. This extremely sensitive scale can detect changes as small as ten- billionths of a kilogram. Rather than using another mass, watt balances measure the mass of a kilogram in terms of electrical and magnetic forces. Those forces can be translated into a number that is related to Planck's constant. The scale is so sensitive that it can detect changes as small as ten- billionths of a kilogram. Lawnmowers, the tides, and even earthquakes on the other side of the world are able to upset the balance. There are many other sources of noise as well. Robinson admits that when he started working on watt balances in the 1. Today, after decades of work, scientists believe they are still five or six years away from setting a new standard. When it does, the metal cylinder in Paris will be replaced by an eight- digit number. Anyone with a watt balance, and a lot of spare time, will be able to measure it for themselves. Mohr says the new kilogram will be worth all the trouble. The new, unchanging number would be a significant improvement over the past. For other uses, see KG. The kilogram or kilogramme (SI unit symbol: kg) is the base unit of mass in the International System of Units (SI) (the Metric system) and is defined as being equal to the mass of the International Prototype of the Kilogram (IPK, also known as . Other traditional units of weight and mass around the world are also defined in terms of the kilogram, making the IPK the primary standard for virtually all units of mass on Earth. Definition. It is also the only SI unit that is still directly defined by an artifact rather than a fundamental physical property that can be reproduced in different laboratories. Three other base units (cd, A, mol) and 1. N, Pa, J, W, C, V, F, . Only 8 other units do not require the kilogram in their definition: temperature (K, . After the International Prototype Kilogram had been found to vary in mass over time relative to its reproductions, the International Committee for Weights and Measures (CIPM) recommended in 2. At its 2. 01. 1 meeting, the CGPM agreed in principle that the kilogram should be redefined in terms of the Planck constant. The decision was originally deferred until 2. Copies of the IPK kept by national metrology laboratories around the world were compared with the IPK in 1. IPK. Name and terminology. In the United Kingdom both spellings are used, with . In 1. 90. 1, however, following the discoveries by James Clerk Maxwell to the effect that electric measurements could not be explained in terms of the three fundamental units of length, mass and time, Giovanni Giorgi proposed a new standard system which would include a fourth fundamental unit to measure quantities in electromagnetism. Mass is an inertial property; that is, it is related to the tendency of an object at rest to remain at rest, or if in motion to remain in motion at a constant velocity, unless acted upon by a force. However, since objects in microgravity still retain their mass and inertia, an astronaut must exert ten times as much force to accelerate a 1. The ratio of the force of gravity on the two objects, measured by the scale, is equal to the ratio of their masses. Kilogramme des Archives. Accordingly, a provisional mass standard was made as a single- piece, metallic artifact one thousand times as massive as the gram. The prototype was presented to the Archives of the Republic in June and on December 1. Archives (Kilogram of the Archives) and the kilogram was defined as being equal to its mass. This standard stood for the next 9. International prototype kilogram. The prototype is manufactured from a platinum. The IPK is made of a platinum alloy known as . The IPK and its six sister copies are stored at the International Bureau of Weights and Measures (known by its French- language initials BIPM) in an environmentally monitored safe in the lower vault located in the basement of the BIPM's Pavillon de Breteuil in Saint- Cloud. Three independently controlled keys are required to open the vault. Official copies of the IPK were made available to other nations to serve as their national standards. These are compared to the IPK roughly every 4. IPK. The IPK is one of three cylinders made in 1. Johnson Matthey, which continues to manufacture nearly all of the national prototypes today. This is a replica for public display, shown as it is normally stored, under two bell jars. The various copies of the international prototype kilogram are given the following designations in the literature: The IPK itself. Located in Saint- Cloud, France. Six sister copies, numbered: K1, 7, 8(4. Colonnetti in Turin (6. However, any changes in the IPK's mass over time can be deduced by comparing its mass to that of its official copies stored throughout the world, a rarely undertaken process called . The only three verifications occurred in 1. For instance, the US owns four 9. Pt. Both of these, as well as those from other nations, are periodically returned to the BIPM for verification. Extraordinary care is exercised when transporting prototypes. In 1. 98. 4, the K4 and K2. Note that none of the replicas has a mass precisely equal to that of the IPK; their masses are calibrated and documented as offset values. For instance, K2. US's primary standard, originally had an official mass of 1 kg. A verification performed in 1. The latest verification performed in 1. Quite unlike transient variations such as this, the US's check standard, K4, has persistently declined in mass relative to the IPK. Check standards are used much more often than primary standards and are prone to scratches and other wear. K4 was originally delivered with an official mass of 1 kg. Over a period of 1. K4 lost 4. 1 . The initial 1. IPK have been nulled. There is the distinct possibility that all the prototypes gained mass over 1. K2. 1, K3. 5, K4. IPK simply gained less than the others. Beyond the simple wear that check standards can experience, the mass of even the carefully stored national prototypes can drift relative to the IPK for a variety of reasons, some known and some unknown. Since the IPK and its replicas are stored in air (albeit under two or more nested bell jars), they gain mass through adsorption of atmospheric contamination onto their surfaces. Accordingly, they are cleaned in a process the BIPM developed between 1. Before the BIPM's published report in 1. The NIST's practice before then was to soak and rinse its two prototypes first in benzene, then in ethanol, and to then clean them with a jet of bi- distilled water steam. Cleaning the prototypes removes between 5 and 6. Further, a second cleaning can remove up to 1. The BIPM even developed a model of this gain and concluded that it averaged 1. Since check standards like K4 are not cleaned for routine calibrations of other mass standards. What has become clear after the third periodic verification performed between 1. It is also clear that the mass of the IPK lost perhaps 5. No plausible mechanism has been proposed to explain either a steady decrease in the mass of the IPK, or an increase in that of its replicas dispersed throughout the world. The root of the problem is often the reporters' failure to correctly interpret or paraphrase nuanced scientific concepts, as exemplified by this 1. September 2. 00. 7 story by the Associated Press published on Phys. Org. com. In that AP story, Richard Davis. Then the AP summarized the nature of issue with this lead- in to the story: . The 1. 18- year- old cylinder that is the international prototype for the metric mass, kept tightly under lock and key outside Paris, is mysteriously losing weight . Like many of the above- linked sites, the AP also misreported the age of the IPK, using the date of its adoption as the mass prototype, not the date of the cylinder's manufacture. This is a mistake even Scientific American fell victim to in a print edition. Moreover, there are no technical means available to determine whether or not the entire worldwide ensemble of prototypes suffers from even greater long- term trends upwards or downwards because their mass . The BIPM's FAQ explains, for example, that the divergence is dependent on the amount of time elapsed between measurements and not dependent on the number of times the artifacts have been cleaned or possible changes in gravity or environment. The IPK has been stored within centimetres of a mercury thermometer since at least as far back as the late 1. The increasing divergence in the masses of the world's prototypes and the short- term instability in the IPK has prompted research into improved methods to obtain a smooth surface finish using diamond turning on newly manufactured replicas and has intensified the search for a new definition of the kilogram. See Proposed future definitions, below. For instance, the newton is defined as the force necessary to accelerate one kilogram at one metre per second squared. If the mass of the IPK were to change slightly, so too must the newton by a proportional degree. In turn, the pascal, the SI unit of pressure, is defined in terms of the newton. This chain of dependency follows to many other SI units of measure. For instance, the joule, the SI unit of energy, is defined as that expended when a force of one newton acts through one metre. Next to be affected is the SI unit of power, the watt, which is one joule per second. The ampere too is defined relative to the newton, and ultimately, the kilogram. With the magnitude of the primary units of electricity thus determined by the kilogram, so too follow many others, namely the coulomb, volt, tesla, and weber. Even units used in the measure of light would be affected; the candela. Yet, despite the best stewardship, the average mass of the worldwide ensemble of prototypes and the mass of the IPK have likely diverged another 6. For instance, the metre is defined as the distance light travels in a vacuum during a time interval of . However, the metre's practical realization typically takes the form of a helium. Now suppose that the official measurement of the second was found to have drifted by a few parts per billion (it is actually extremely stable with a reproducibility of a few parts in 1. Scientists performing metre calibrations would simply continue to measure out the same number of laser wavelengths until an agreement was reached to do otherwise. The same is true with regard to the real- world dependency on the kilogram: if the mass of the IPK was found to have changed slightly, there would be no automatic effect upon the other units of measure because their practical realizations provide an insulating layer of abstraction. Any discrepancy would eventually have to be reconciled though, because the virtue of the SI system is its precise mathematical and logical harmony amongst its units. If the IPK's value were definitively proven to have changed, one solution would be to simply redefine the kilogram as being equal to the mass of the IPK plus an offset value, similarly to what is currently done with its replicas; e.
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