BMI classification and cut-off point

BMI classification


Body Mass Index (BMI) is a simple
index of weight-for-height that is commonly used to classify underweight,
overweight and obesity in adults. It is defined as the weight in kilograms
divided by the square of the height in metres (kg/m2).
For example, an adult who weighs 70kg and whose height is 1.75m will have a BMI
of 22.9.


BMI = 70 kg / (1.75 m)2 = 70 / 3,0625 = 22.9


Table 1: The International Classification of adult
underweight, overweight and obesity according to BMI

BMI values are age-independent and the same for both sexes. However, BMI may not correspond to the same degree of fatness in different populations due, in part, to different body proportions. The health risks associated with increasing BMI are continuous and the interpretation of BMI gradings in relation to risk may differ for different populations.

In recent years, there was a growing debate on whether there are possible needs for developing different BMI cut-off points for different ethnic groups due to the increasing evidence that the associations between BMI, percentage of body fat, and body fat distribution differ across populations and therefore, the health risks increase below the cut-off point of 25 kg/m2 that defines overweight in the current WHO classification.


There had been two previous attempts to interpret the BMI cut-offs in Asian and Pacific populations3,4, which contributed to the growing debates. Therefore, to shed the light on this debates, WHO convened the Expert Consultation on BMI in Asian populations (Singapore, 8-11 July, 2002)5.


The WHO Expert Consultation5 concluded that the proportion of Asian people with a high risk of type 2 diabetes and cardiovascular disease is substantial at BMI's lower than the existing WHO cut-off point for overweight (= 25 kg/m2). However, the cut-off point for observed risk varies from 22 kg/m2 to 25 kg/m2 in different Asian populations and for high risk, it varies from 26 kg/m2 to 31 kg/m2 . The Consultation, therefore, recommended that the current WHO BMI cut-off points (Table 1) should be retained as the international classification.

But the cut-off points of 23, 27.5, 32.5 and 37.5 kg/m2 are to be added as points for public health action. It was, therefore, recommended that countries should use all categories (i.e. 18.5, 23, 25, 27.5, 30, 32.5 kg/m2 , and in many populations, 35, 37.5, and 40 kg/m2) for reporting purposes, with a view to facilitating international comparisons.

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Low BMI but high percent body fat : implications of obesity cutoffs

To compare the different correlations of body mass index (BMI) and percent body fat (BF%) with other ethnic groups and to evaluate the appropriateness of Asia-Pacific redefining obesity criteria in the Taiwanese population. The corresponding BF% to BMI cutoffs of overweight and obesity will also be studied.

A cross-sectional epidemiological survey.

SUBJECTS: A total of 509 male and 570 female Taiwanese subjects aged greater than or equal to20 y sampled by the systematic stratified clustering sampling method were analyzed.

MEASUREMENTS: BMI was obtained by body weight (kg) divided by squared body height (m2). The estimated BMI (BMIe) was deduced from the Caucasian-based four-compartment equation (4C). BF% measured by the methods of dual-energy X-ray absorptiometry (DXA) or Caucasian-based 4C were used and abbreviated as DXA-BF and 4C-BF, respectively.

RESULTS: The curvilinear relationship between age and BMI or DXA-BF was established. When compared by age-stratified groups, Taiwanese subjects had a higher BF% (4C-BF) in any given BMI than Caucasians. That is, the level of 4C-BF for BMIgreater than or equal to25 kg/m2 in Taiwanese subjects was similar to BMIgreater than or equal to30 kg/m2 in Caucasians. The BMIe values of 25 and 30 kg/m2 were nearly equal to the BMIs of 23.6 and 25.3 kg/m2 in males, and 22.7 and 24.8 kg/m2 in females, respectively. The 4C-BF of 25% was nearly equal to a BMI of 26.2 kg/m2 in males, and 35% was equal to a BMI of 24.4 kg/m2 in females. Consequently, the DXA-BF cutoffs for BMIs of 23 and 25 kg/m2 were compatible to 23 and 25% in males, and 35 and 38% in females, respectively.

CONCLUSION: It was demonstrated that Taiwanese subjects had a relatively lower BMI but a higher BF% than Caucasians. In general, the newly proposed Asia-Pacific BMI cutoffs for overweight (greater than or equal to23 kg/m2) and obesity (greater than or equal to25 kg/m2) may be acceptable to both male and female Taiwanese subjects. The corresponding BF% (DXA-BF) cutoffs for obesity would be 25% in male and 38% in female Taiwanese subjects, respectively.

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ADVANTAGES OF WEIGHT LOST

Weight loss has advantages in reducing cardiovascular risk factors and other obesity associated diseases.

Benefits of weight loss on health risks in obesity (Evidence Level B) Health Risk Benefits of 10 kg weight loss in a 100 kg subject
1. Blood Pressure
  • 10 mmHg reduction systolic BP
  • 20 mmHg reduction diastolic BP
  • Weight loss also reduces the need for medication in hypertensive patients
2. Lipids
  • 10% reduction in Total Cholesterol
  • 15% reduction in LDL-cholesterol
  • 30% reduction in Triglycerides
  • 8% increase in HDL-cholesterol
3. Diabetes
  • >50% reduction in risk of developing DM (Weight loss of 6.8 kg is associated with 58% reduction in incidence of diabetes, at 3 years in the Diabetes Prevention Programme)
  • 30-50% reduction in Fasting plasma glucose
  • 15% reduction in HbA1c
4. Osteoarthritis
  • Decrease BMI > 2kg/m2 associated with more than 50% decreased risk for developing osteoarthritis
5. Mortality
  • 20 –25% reduction all – cause mortality
  • 30 – 40% reduction diabetes related death
  • 40 – 50% reduction in obesity-related cancer death

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BMI and Waist circumference




BMI and Waist circumference - The New Definition of Obesity

This is the most established and widely used measurement and is defined as:


The current WHO classification states that the cut-off points for overweight and obesity is 25 and 30 kg/m2 respectively. However, it has become increasingly clear that there is a high prevalence of type 2 diabetes mellitus and cardiovascular risk factors in parts of Asia below those cut-off points. Evidence from several Asian countries are now available including Hong Kong , Singapore, China, India, and Japan to show that the risk of co morbidities begin to rise at lower BMI values. Many Asian populations have a higher body fat percent at similar BMI, compared with Caucasian/European populations. Thus, based on current evidence, the following classification of weight by BMI according to risk of co-morbidities is recommended.

BMI (kg/m2) Classification ( Risk of co-morbidities)
<18.5 -Underweight ( Low but increased risk of other clinical problems)
18.5–22.9 - Normal ( Average)
23.0–24.9 - Overweight ( Increased)
25.0–29.9 - Obese I (Moderate )
≥ 30.0 - Obese II (severe)


Waist circumference


Waist circumference (WC) measurement is simple, reliable, and correlates well with abdominal fat content irrespective of the BMI. WC is also an independent risk factor for cardiovascular diseases. It is most useful in individuals who are in the normal and overweight categories of the BMI. In those with BMI > 35 kg/m2 it is unnecessary to measure WC as it looses its predictive value.


The current WHO recommendations suggest that the WC of 94 cm and 80 cm is associated with an increased risk in man and woman respectively. However, it has become increasingly clear that there is a high prevalence of type 2 diabetes melitus and cardiovascular risk factors in parts of Asia below those cut-off points. Evidence from several Asian countries are now available including Hong Kong, Singapore and China. Thus, based on current evidence, the following waist circumference is associated with an increased risk

Men> 90 cm (35.5")
Women> 80 cm (31.5")


more articles about Waist circumference: http://bmi-formula.blogspot.com/2008/11/bmi-and-waist-circumference.html

http://nutritional-pyramid.blogspot.com/

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best way to lose fat quickly

Hate my ugly tummy fat. There must be a simple way to get rid of it without starvation diets and heavy exercise. There must be a simple way to get rid of it fast. So what is the best way to lose fat quickly.


It sort of just sticks out like a pot. I suppose that is why they call it a pot belly. When I sit down it sort of oozes out in a roll and hangs down on my sides. Horrible, ugly tummy fat. Just pure ugly fat. All caused by a lifetime of indulgence I suppose. I do love my chocolate cake and just about any other sweet thing you can mention. What about black forest cake or pavlova.

Now I am paying the price. This ugly fat. And that is all it is. Just fat. I have been doing some research and I don't really need to lose weight per se although that will naturally go if I can get rid of this fat. If I can say just target this fat and get rid of it then I will be naturally losing weight if you know what I mean. So how do I target just this fat and get rid of it. What is the best way to lose fat quickly.

I don't want one of those fancy diets where I can lose lots of weight real easy but it just turns out to be water weight or muscle weight etc. and not really moving any actual fat. Because those sorts of diets usually just make you fatter in the end because all the weight just comes back on. I want something to just target this fat roll of mine. To get rid of it quickly and easily and get rid of it for good. No more coming back on. There must be a way.

Well, I have still been researching and I have discovered that this nutrition stuff is a huge subject. I suppose that is why so many of us have been caught with crook diets that have done us no good. We just don't understand the mechanics of it all. Well it is a complex subject. What we need is a system that has been tried and true and works and puts us on the way to slim trim and happiness.

Wouldn't that be nice. Well, I ask again. There must be a best way to lose fat quickly out there.

In my research I discovered that our bodies are really complex things in regard to nutrition. We knew that but the nitty gritty is interesting. After all, when we eat that chocolate cake that our body doesn't need, we need it because it tastes good, our body will say to itself. What a waste. A lovely piece of chocolate cake that I don't need right now but I may need it later so I better save it. Where shall I save it. What about that lovely layer of fat on the tummy. After all, that is where last weeks sponge pudding is stored and the week before was those lovely dumplings. You know what I mean.

So our body is not stupid. All we have to do is train it, or trick it into thinking a bit differently and we will notice a vast difference in what happens to that chocolate cake. We will need to eat a bit more than we do now but in smaller lots and more often during the day. At least we are not going to be hungry. Might have to adjust a little what we eat on all these extra meals but apparently this is just one of the ways we can start to reverse our body shape in regard to that ugly fat. How about two pounds in a week. That is fat gone forever and we can keep at it till we are that perfect lean trim thing we all long for.

It sounds good to me and of course there is a lot more to know but my word count has gone crazy again. I will add a link here so you can read the whole article. Enjoy!

Opps...one more, find out here for "How To Lose Weight Quick" easily.
www.one2lose.com

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BMI formula

This is the most established and widely used measurement and is defined as
The current WHO classification states that the cut-off points for overweight and obesity
is 25 and 30 kg/m2 respectively. However, it has become increasingly clear that there
is a high prevalence of type 2 diabetes mellitus and cardiovascular risk factors in parts of
Asia below those cut-off points. Evidence from several Asian countries are now available
including Hong Kong, Singapore, China, India, and Japan to
show tha t the risk of co morbidities begin to rise at lower BMI values. Many Asian
populations have a higher body fat percent at similar BMI, compared with
Caucasian/European populations. Thus, based on current evidence, the following
classification of weight by BMI according to risk of co-morbidities is recommended.

BMI (kg/m2) Classification Risk of co-morbidities
 <> | Underweight Low (but increased risk of other clinical problems)
18.5–22.9 Normal Average
23.0–24.9 Overweight Increased
25.0–29.9 Obese I Moderate
≥ 30.0 Obese II Severe

Waist circumference

Waist circumference (WC) measurement is simple, reliable, and correlates well with abdominal fat content irrespective of the BMI. WC is also an independent risk factor for cardiovascular diseases. It is most useful in individuals who are in the normal and overweight categories of the BMI. In those with BMI > 35 kg/m2 it is unnecessary to measure WC as it looses its predictive value.


The current WHO recommendations suggest that the WC of 94 cm and 80 cm is associated with an increased risk in man and woman respectively. However, it has become increasingly clear that there is a high prevalence of type 2 diabetes melitus and cardiovascular risk factors in parts of Asia below those cut-off points. Evidence from several Asian countries are now available including Hong Kong, Singapore and China. Thus, based on current evidence, the following waist circumference is associated with an increased risk




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