With all the talk about it these days, you might be wondering, “What is BMI?” There's no magic to it, no secret formula, even though sometimes the way it's talked about it sounds like some sort of mantra for weight loss and health. BMI isn't a meditation or an exercise or diet plan, it's simply the measure of your body mass. It compares your weight and height, and boils that ratio down to a number. Depending where your number is on the scale, it tells you if you're underweight for your height, overweight, or obese.
So what is BMI, in general? BMI, or body mass index, is a tool of body mass measurement that was created in the early 1800s by Adolphe Quetelet. This is why sometimes you might see BMI referred to as the Quetelet index. Adolphe Quetelet was mathematician, statistician, and an astronomer, among other things. He developed the BMI while working on social physics. The BMI is still used today with very few variations on his original invention.
What is BMI, specifically? BMI doesn't measure body fat, but instead compares a person's weight and height to estimate a healthy body weight for that person's height. It's widely used to determine if someone is technically overweight or obese. Though it's the not the final tool in diagnosing obesity or overweight, because it's not without its flaws for certain body types, it's still in use in the medical community.
The formula for BMI is simple: Take your height in meters squared (your height times itself) and then divide your weight in kilograms by that number. For example, if I'm 5 feet tall, that's about 1.5 meters. 1.5 squared (1.5 times 1.5) equals 2.5. If I weigh 120 pounds, that's about 54.5 kilograms. So I need to divide 54.5 by 2.5 which gives me a result of 21.8 as my BMI. So what does that number mean? A BMI of 18.5 or below indicates that an individual is underweight. The normal weight range is from 18.5 to 24.9. Overweight people will calculate a BMI of 25 to 29.9. A BMI of 30 or greater indicates obesity. Someone five feet tall weighing 120 pounds falls into the normal weight range.
Where BMI fails is with extremely muscular people. It doesn't distinguish between muscle and fat, instead using total weight as the measure. So according to the BMI, bodybuilders are likely to measure as obese which is inaccurate. Most athletes like wrestlers, footballs players and any athletes with a large amount of lean muscle are going to measure as overweight or obese. But for most people, BMI is a fairly accurate measure of their level of underweight or overweight.
Now that you know the formula, you know that BMI is as simple as a single math problem, and a single number. Next time you're faced with the question, “What is BMI?” you'll know there's no magic to it, it's simply a measure of a person's body weight compared to his or her height.
Showing posts with label BMI Charts. Show all posts
Showing posts with label BMI Charts. Show all posts
Saturday, May 29, 2010
Friday, May 28, 2010
Tips About the BMI Index
The BMI Index is a tool that was invented in the early 1800s. While there aren't many health and fitness tools that were created in the eartly 1800s that we're still using today just as they were, the BMI index is relatively unchanged in almost 200 years. It's still a popular tool used to figure out if a person's weight is healthy. The BMI simply compares your weight to your height and decides if you're underweight, a normal weight, overweight or obese. Most of us can look in the mirror or notice whether or not we're having to squeeze into our pants, and determine this without the use of numbers and calculations. But that doesn't stop the BMI from being widely used by doctors, and worse, insurance companies.
Insurance companies frequently use a person's BMI to determine if the person is a risk to insure. Health insurance costs can be higher for those who have a BMI in the overweight or obese range, and life insurance can be higher or it can be refused completely. While it's within these companies' rights to refuse to insure anyone, the use of the BMI index to make that determination represents flawed thinking, unless other factors are considered, too.
The BMI Index determines a person's BMI by dividing their weight by their height squared (their height times itself). When kilograms and meters are converted into pounds and feet or inches, the formula changes very slightly, but the resulting BMI number is very close the number obtained by using kilograms and meters. For most people, the BMI Index is a decent measure of their weight in proportion to their height. But for some, it comes up with a label that's far off.
Consider a championship bodybuilder. He's one of the best in the world in the lightweight division, at 5' 3” and 154 pounds. The man is solid muscle, and he's in amazing physical shape. The BMI Index says he's overweight and needs to lose weight. When you take his height times itself and divide that into his weight, he comes up with a BMI of almost 27. The cut-off for normal weight is 24.9. Clearly, he's not overweight, with barely an ounce of body fat anywhere. But an insurance company won't care about that, they could refuse him insurance based on his 'high-risk' BMI.
Once you've used the formula to figure your number on the BMI Index, you can see where you rank as far as healthy weight. A person is underweight with BMI of 18.5 or below. The normal weight range is from 18.5 to 24.9. From 25 to 29.9 indicates that you're overweight. And anyone with a BMI of 30 or over is considered obese. Try plugging in some professional athletes' heights and weights, and see how many are classified obese with the BMI Index.
This makes it clear that while it's a valuable tool, common sense, appearance and body fat must be considered along with the BMI Index to determine a person's ideal weight.
Insurance companies frequently use a person's BMI to determine if the person is a risk to insure. Health insurance costs can be higher for those who have a BMI in the overweight or obese range, and life insurance can be higher or it can be refused completely. While it's within these companies' rights to refuse to insure anyone, the use of the BMI index to make that determination represents flawed thinking, unless other factors are considered, too.
The BMI Index determines a person's BMI by dividing their weight by their height squared (their height times itself). When kilograms and meters are converted into pounds and feet or inches, the formula changes very slightly, but the resulting BMI number is very close the number obtained by using kilograms and meters. For most people, the BMI Index is a decent measure of their weight in proportion to their height. But for some, it comes up with a label that's far off.
Consider a championship bodybuilder. He's one of the best in the world in the lightweight division, at 5' 3” and 154 pounds. The man is solid muscle, and he's in amazing physical shape. The BMI Index says he's overweight and needs to lose weight. When you take his height times itself and divide that into his weight, he comes up with a BMI of almost 27. The cut-off for normal weight is 24.9. Clearly, he's not overweight, with barely an ounce of body fat anywhere. But an insurance company won't care about that, they could refuse him insurance based on his 'high-risk' BMI.
Once you've used the formula to figure your number on the BMI Index, you can see where you rank as far as healthy weight. A person is underweight with BMI of 18.5 or below. The normal weight range is from 18.5 to 24.9. From 25 to 29.9 indicates that you're overweight. And anyone with a BMI of 30 or over is considered obese. Try plugging in some professional athletes' heights and weights, and see how many are classified obese with the BMI Index.
This makes it clear that while it's a valuable tool, common sense, appearance and body fat must be considered along with the BMI Index to determine a person's ideal weight.
Thursday, May 27, 2010
The Truth About Mothers and their Daughters' Resemblance on BMI Charts
Is it true that mothers and their daughters' resemblance on BMI is a sure thing? It's easy to assume that a daughter might take after her mother's eating habits and have a similar BMI as her mother, for many reasons. But they might not be the reasons you'd think. But first, let's make it clear what BMI is.
BMI or body mass index is nothing more than the measure of a person's weight in relation to her height. A person's weight in kilograms is divided by a person's height in meters, squared (which is simply a person's height times itself—if I'm 1.5 meters tall, I would take 1.5 times 1.5). The resulting number is her BMI. A normal BMI is anything from 18.5 to 24.5, and 25 to 29.9 is considered overweight, with anything above that considered obese. A BMI below 18.5 is considered underweight. BMI is a good general measurement for most people, although very muscular people usually measure as overweight or obese because BMI doesn't distinguish between muscle weight and fat weight.
So, back to mothers and their daughters' resemblance on BMI, does it guarantee that a daughter will be overweight if her mother has a high BMI? Will a normal weight mother raise a normal weight daughter? Will the daughter be underweight if the mother is too skinny? While nothing is certain 100% of the time, there are some factors that push those answers more toward a yes than a no.
Genetics do play a part in a person's tendency toward staying thin or gaining weight. Hereditary factors like body type are impossible to change. Tendency toward a slow metabolism can be boosted by exercise, good nutrition and a healthy lifestyle, but genetics will help determine how easy or difficult keeping a high metabolism may be for a daughter.
The environment is a huge factor. When a mother is overweight, for example, and she generally cooks for the family, the family eat what she eats to a large degree. So it's easy to see why mothers and their daughters' resemblance on BMI is often very similar. Living with a person, especially someone with the influence a mother has on a daughter, also tends to shape a person's attitudes. So if the mother is very active, eats healthy and stays physically fit, it's more likely than a child, especially a daughter, will do the same. Conversely, a mother who is overweight, rarely gets exercise and doesn't seem overly concerned with weight loss or health is likely to bring up her daughter with the same outlook. In both cases, it's no surprise that their BMIs might be similar.
So not only do the attitudes about food and fitness filter down from mothers to daughters, the type of food eaten, and even the amount of food eaten, can filter down, too. Mothers and their daughters' resemblance on BMI charts is no coincidence, and only shows the need for families to be aware of their health and fitness even when children are small.
BMI or body mass index is nothing more than the measure of a person's weight in relation to her height. A person's weight in kilograms is divided by a person's height in meters, squared (which is simply a person's height times itself—if I'm 1.5 meters tall, I would take 1.5 times 1.5). The resulting number is her BMI. A normal BMI is anything from 18.5 to 24.5, and 25 to 29.9 is considered overweight, with anything above that considered obese. A BMI below 18.5 is considered underweight. BMI is a good general measurement for most people, although very muscular people usually measure as overweight or obese because BMI doesn't distinguish between muscle weight and fat weight.
So, back to mothers and their daughters' resemblance on BMI, does it guarantee that a daughter will be overweight if her mother has a high BMI? Will a normal weight mother raise a normal weight daughter? Will the daughter be underweight if the mother is too skinny? While nothing is certain 100% of the time, there are some factors that push those answers more toward a yes than a no.
Genetics do play a part in a person's tendency toward staying thin or gaining weight. Hereditary factors like body type are impossible to change. Tendency toward a slow metabolism can be boosted by exercise, good nutrition and a healthy lifestyle, but genetics will help determine how easy or difficult keeping a high metabolism may be for a daughter.
The environment is a huge factor. When a mother is overweight, for example, and she generally cooks for the family, the family eat what she eats to a large degree. So it's easy to see why mothers and their daughters' resemblance on BMI is often very similar. Living with a person, especially someone with the influence a mother has on a daughter, also tends to shape a person's attitudes. So if the mother is very active, eats healthy and stays physically fit, it's more likely than a child, especially a daughter, will do the same. Conversely, a mother who is overweight, rarely gets exercise and doesn't seem overly concerned with weight loss or health is likely to bring up her daughter with the same outlook. In both cases, it's no surprise that their BMIs might be similar.
So not only do the attitudes about food and fitness filter down from mothers to daughters, the type of food eaten, and even the amount of food eaten, can filter down, too. Mothers and their daughters' resemblance on BMI charts is no coincidence, and only shows the need for families to be aware of their health and fitness even when children are small.
Wednesday, May 26, 2010
The Truth About BMI, Body Fat and Health
Though one of the most popular tools used today to determine whether someone is at a healthy weight or not is the BMI, body fat and lean muscle tissue don't figure into the equation. This has led many experts to discount BMI as an archaic measurement that isn't accurate for many people. What is BMI, and why is it a good measure for some, maybe, and completely wrong for others?
BMI, or body mass index, was created in the early 1800s by Adolphe Quetelet. Because of that, it's sometimes called the Quetelet index. It's nothing more than a way of comparing a person's weight to his or her height, and determining if his or her weight falls into a healthy and normal range. The BMI is still used today pretty much as it was when Quetelet invented it.
The formula for figuring BMI (body fat, bone and frame size, muscle and body type aren't included in that) is this: Take your height in meters squared (your height times itself) and divide your weight in kilograms by that number. For example, if I'm 5 feet tall, that's about 1.5 meters. To square that number, take 1.5 times 1.5. The result of that is 2.5. So if I weigh 120 pounds, that's about 54.5 kilograms. Divide 54.5 by 2.5 and I get 21.8 as my BMI. The normal weight range is from 18.5 to 24.9, so 21.8 is classified as a normal weight. Underweight is considered 18.5 and below, while overweight people will calculate a BMI of 25 to 29.9. A BMI of 30 or greater indicates obesity.
BMI, body fat and general health can all be used as signs of how fit a person is. But where general health is pretty self-explanatory and the percentage of body fat clearly shows whether a person gets enough exercise or not, BMI is a bit trickier.
People with a lot of muscle don't show accurate BMI readings. Because muscle weighs so much heaver than fat but takes up less space, a relatively small statured person can carry a lot of muscle weight without looking huge. BMI doesn't take that into account. Football players, professional wrestlers, bodybuilders, and virtually any athlete who has a lot of muscle is going to measure as overweight and even obese according to the BMI. So it's not accurate for them. Is it accurate for everyone else?
The answer to that is yes, and no. It depends on you. The BMI typically doesn't show an accurate result for children. And extremely tall or large-framed people will show overweight or obese classifications more easily because of the extra weight from their bones and muscles. So for very short, tall or muscular people, the BMI appears to not be a good tool.
There's also no distinguishing between men and women in the BMI. Body fat is more natural for women who are supposed to have more than men, so some sort of distinction in the measurement of the sexes would help the BMI's accuracy.
BMI, or body mass index, was created in the early 1800s by Adolphe Quetelet. Because of that, it's sometimes called the Quetelet index. It's nothing more than a way of comparing a person's weight to his or her height, and determining if his or her weight falls into a healthy and normal range. The BMI is still used today pretty much as it was when Quetelet invented it.
The formula for figuring BMI (body fat, bone and frame size, muscle and body type aren't included in that) is this: Take your height in meters squared (your height times itself) and divide your weight in kilograms by that number. For example, if I'm 5 feet tall, that's about 1.5 meters. To square that number, take 1.5 times 1.5. The result of that is 2.5. So if I weigh 120 pounds, that's about 54.5 kilograms. Divide 54.5 by 2.5 and I get 21.8 as my BMI. The normal weight range is from 18.5 to 24.9, so 21.8 is classified as a normal weight. Underweight is considered 18.5 and below, while overweight people will calculate a BMI of 25 to 29.9. A BMI of 30 or greater indicates obesity.
BMI, body fat and general health can all be used as signs of how fit a person is. But where general health is pretty self-explanatory and the percentage of body fat clearly shows whether a person gets enough exercise or not, BMI is a bit trickier.
People with a lot of muscle don't show accurate BMI readings. Because muscle weighs so much heaver than fat but takes up less space, a relatively small statured person can carry a lot of muscle weight without looking huge. BMI doesn't take that into account. Football players, professional wrestlers, bodybuilders, and virtually any athlete who has a lot of muscle is going to measure as overweight and even obese according to the BMI. So it's not accurate for them. Is it accurate for everyone else?
The answer to that is yes, and no. It depends on you. The BMI typically doesn't show an accurate result for children. And extremely tall or large-framed people will show overweight or obese classifications more easily because of the extra weight from their bones and muscles. So for very short, tall or muscular people, the BMI appears to not be a good tool.
There's also no distinguishing between men and women in the BMI. Body fat is more natural for women who are supposed to have more than men, so some sort of distinction in the measurement of the sexes would help the BMI's accuracy.
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