Is BMI a good measure of health?

Recently, my government has increased it’s focus on its citizens adopting a healthy lifestyle. Today, I decided to look into one metric that is commonly used to determine a population’s health.

What is BMI?

Body Mass Index (BMI) is a person’s weight in kilograms divided by the square of height in meters. A high BMI can be an indicator of high body fatness. BMI can be used to screen for weight categories that may lead to health problems but it is not diagnostic of the body fatness or health of an individual.

What is it used for?

BMI is mainly used to assess weight status of a population. It is a simple screening tool to estimate a person’s body fat, but should be used in conjunction with other body composition tests before a diagnosis is to be made. This is because BMI is unable to discern between body fat percentage and lean mass.

How accurate is it?

This is a tricky question to answer. It’s accuracy differs between populations.

For example, in the USA and Singapore, the use of BMI actually under-diagnoses the prevalence of obesity.

In this study, it was observed that the use of BMI underdiagnosed obesity by 30%!
Accuracy of Body Mass Index to Diagnose Obesity In the US Adult Population

BMI-defined obesity (≥ 30 kg/m2) was present in 21% of men and 31% of women, while BF %-defined obesity was present in 50% and 62%, respectively.

Our findings also suggest that the magnitude of the obesity epidemic may be greatly underestimated by the use of BMI as the marker of obesity 35. In our results, BMI showed an unacceptable low sensitivity for detecting body fatness, with more than half of obese subjects (by body fat measurement) being labeled as normal or overweight by BMI. The true prevalence of obesity might be strikingly higher than that estimated by BMI.

In Singapore, it was observed that the accuracy of BMI differs between ethnic groups.
The paradox of low body mass index and high body fat percentage among Chinese, Malays and Indians in Singapore

RESULTS: Compared with body fat percentage (BF%) obtained using the reference method, BF% for the Singaporean Chinese, Malays and Indians were under-predicted by BMI, sex and age when an equation developed in a Caucasian population was used. The mean prediction error ranged from 2.7% to 5.6% body fat. The BMI/BF% relationship was also different among the three Singaporean groups, with Indians having the highest BF% and Chinese the lowest for the same BMI. These differences could be ascribed to differences in body build. It was also found that for the same amount of body fat as Caucasians who have a body mass index (BMI) of 30 kg/m2 (cut-off for obesity as defined by WHO), the BMI cut-off points for obesity would have to be about 27 kg/m2 for Chinese and Malays and 26 kg/m2 for Indians.

If obesity is defined as excess body fat rather than excess weight, the obesity cut-off point for Singaporeans should be 27 kg/m2 instead of 30 kg/m2. The lowering of the cut-off point for obesity would more than double the prevalence figures in Singapore.

In addition, the study authors also noted that the use of BMI underdiagnosed the prevalence of obesity in Singapore by at least 10%.

Generally, if the cut-off point for obesity in Singapore were lowered to 27 kg/m2, this would have immense impact on the prevalence of obesity among the adult Singapore population. Compared to a BMI cut-off point of 30 kg/m2 the prevalence would increase in females from 6.5% to 15.4% and in males from 5.2% to 17.3%.

Interestingly, it is the opposite for Korea. The use of BMI actually over-diagnosed obesity.

Diagnostic Performance of Body Mass Index Using the Western Pacific Regional Office of World Health Organization Reference Standards for Body Fat Percentage

In the present study, obesity was identified in 38.7% of men and 28.1% of women using body mass index (≥25 kg/m2) and in 25.2% of men and 31.1% of women using body fat percentage. A body mass index cut-off ≥25 kg/m2 had high specificity (89%, men; 84%, women) but poor sensitivity (56%, men; 72%, women).

On the basis of BF%, 25.2% of men and 31.1% of women were classified as obese in the present study compared to 50% of men and 62% of women in American populations (10). Thus, BF% better reflects the current status than population-specific cut-off points for BMI for international comparisons of the prevalence of obesity. The prevalence of BF%-defined obesity was higher in women than in men in Korea, which suggests that Korean women have less lean mass than do Korean men.

What is the significance of BMI?

As mentioned earlier it is mainly used a health indicator of a population but not an individual.

High and low BMI have been correlated with increased mortality rates. However, the increased risk of mortality observed in underweight people could at least partly be caused by residual confounding from prediagnostic disease. i.e. It’s a reverse causation, people are underweight due to their pre-existing conditions (eg. cancer).

An increase in BMI has been correlated with an increased risk for a myriad of diseases such as heart disease and diabetes.

Advertisements

Is “Less Sugar” Always Better?

Healthier food costs more because slow demand leads to inadequate economies of scale: Chee Hong Tat

During a parliament session Senior Minister of State (SMS) for Health Chee Hong Tat attributed the increased cost of “heathier” food options to lack of demand.

“During the initial phase when the healthier products are being introduced, they will have to go through this phase where consumers are getting used to it and the demand is not quite picking up,” he said.

“So when you produce it and there’s inadequate economies of scale, the merchant finds it difficult to price it at a very competitive level.”

Mr Chee was responding to Member of Parliament for Bishan-Toa Payoh GRC Chong Kee Hiong, who asked why healthier foods tend to be more expensive than less healthy options.

As for his question on the price disparity, Mr Chong clarified that he was referring to two variations of the same brand of kaya. The low sugar option costs S$1 more, he said.

Out of interest, I went to take a look at the two types of kaya from Fairprice private label:
Fairprice Nonya Kaya – Less Sugar 400G – $3.95
FairPrice Nonya Kaya 410G – $2.65

Below I have made a comparison table of the macronutrients.

Normal Less Sugar
Serving(g) 16 16
Calories(kcal) 48 49
Protein(g) 0.8 0.6
Total Fat(g) 1.4 0.8
Carbohydrate(g) 8 9.9

Not only does the less sugar version contain more calories, it also contains MORE carbohydrates and LESS protein.

To reduce the sugar, they added maltitol, a cheap sugar alcohol that has half the calories of sugar per gram and actually cost less than sugar for the same unit of sweetness
Source: http://www.sugar-and-sweetener-guide.com/maltitol.html

So is the “heathier” option always healthier?

Best to be a smart consumer and always remember to always check the nutrition label! Caveat emptor.

 

oft , oft , oft

Recently I’ve been busy learning python. This is a short summary of what I’ve learned so far, mainly for accountability purposes.

I learned how to scrape websites using BeautifulSoup and that I should include a sleep(x) between requests so as not to hammer the site and get my IP banned.

I learned how to use NLTK to generate random sentences with a seed word using ngrams.

Couple of examples using seed words “Lady” and “Man”. Experimented with using bigrams, trigrams and quadgrams (sp?)

Lady of Chertsey , Who said , who loved to see little folks merry ; So he made them a Book , and with laughter they shook At the fun

Lady of Clare , Who said , oft , oft , oft , oft , oft , oft , oft , oft , oft , oft , oft , oft , oft , oft , oft , oft , oft

Man of the Isles , Whose face with red ochre . When they silenced his clamor . By smashing that Person of Chili . There was a Young Lady whose eyes Were unique as Angels kenn he fell , from SYRIAN ground , That nasty Old Person of Chili . There was dire , As Gods , and dazling Arms ,

Lady of Parma , Which drowned that Old Man of Chertsey , Who possessed a large Cow , but buns , That dolorous Man of the air could repose ; But they gave him awake they fed them on Snails , and weighed them in scales ; When she ceased to repine , That capricious Young Lady of Ischia , Whose toilette was None

Man by him seduc’t , but on the harp , for the ease you find To Noon he fell By FONTARABBIA . For Spirits when by the Vision led His eye survay ‘d the cold . There was an Old Man of Whitehaven . There was a Young Lady of Prague , His utmost power oppos’d In dubious Battel on the will

Lady whose chin Resembled the point of Crete , Whose toilette was far from complete ; He sat on whose nose Most birds of the Wrekin , Whose head was as the bush ! ” There was an Old Man with a gong . There was horribly vague ; But in handing his daughter , Which refreshed that virulent Bull

I learned that animals from different countries have different accents. And different countries have different sounds for sounds.

For example: In English, a knocking on the door is “knock knock” but in Polish the sound is heard as “puk puk”. In English, pigs go “oink oink” but in Korea pigs go “GGOOL GGOOL” (꿀꿀).

And that’s it.

running

I read an article recently, titled “Running Is Stupid, So Why Do I Do It?”

And it reminded me of this passage from “The Curse of Lono” by Hunter S. Thompson

There are 30,000 of them now and they all are running for their own reasons. And this is the angle — this is the story: Why do these buggers run? What kind of sick instinct, stroked by countless hours of brutal training, would cause intelligent people to get up at 4 in the morning and stagger through the streets of Honolulu for 26 ball-busting miles in a race that less than a dozen of them have any chance of winning? This is the question we have come to Hawaii to answer — again. They do not enter to win. They enter to survive, and go home with a T-shirt. That was the test and the only ones who failed were those who dropped out.

Most people grapple with the fact that I run as a hobby. For leisure and not punishment. They often ask what am I training for and I answer nothing. I’m essentially a hobby yogger.

I don’t post my runs on social media and neither do I talk about it unless prompted to. I feel that running is a private activity and try to keep it that way. Yes, I do run in public places, but at same time I am by myself. The only participant in this impromptu race to nowhere. Challenging myself to be better.. for no apparent purpose.

I usually run by time or direction and see where my feet take me. I do get lost often and usually have to ask for directions. But I love that. The people I meet are always so helpful, which is a refreshing change from the barbaric hordes you battle with during rush hour.

So if running is stupid and hard, why do I do it?  I honestly don’t know. But I do know not running is harder.

crisis

In American Beauty (1999), Kevin Spacey stars as a depressed middle-aged man who suffers a midlife crisis after falling in love with his daughter’s best friend. This movie helped popularize many of the iconic images we now associate with the midlife crisis – buying a flashy car, vanity and trying to be relevant again.

It is believed that the midlife crisis is brought about when one starts to examine one’s life circumstances. Their health, career and relationships. How satisfied are they with their current condition and how to improve or rework them. And it seems that even apes experience midlife crisis.

The midlife crisis is usually triggered by a period of stress or depression. And women  might be more susceptible to it due to life experiences which are unique to women such as pregnancy and menopause.

According to the National Alliance on Mental Illness, most life experiences attributed to depression are unique to women, such as post-partum changes, infertility, and hormonal fluctuation. Evidence has shown that people suffering from depression have different brain chemistry which is altered by hormones that control emotions and mood. These hormones are particularly heightened during certain times in a women’s life, including postpartum period and menopause.

In addition, it seems that most people experience a lull in their 40s-50s. When scholars started studying the “science” of happiness, they noticed a recurrent pattern that is now known as the U-curve:

“Whatever sets of data you looked at,” Blanchflower told me in a recent interview, “you got the same things”: life satisfaction would decline with age for the first couple of decades of adulthood, bottom out somewhere in the 40s or early 50s, and then, until the very last years, increase with age, often (though not always) reaching a higher level than in young adulthood. The pattern came to be known as the happiness U-curve.

However, although most people seem to experience this nadir in their lives, how badly their happiness dips is dependent on a slew of other factors besides age such as income, marital status, employment. For example, it appears that people in wealthier countries tend to be more dis-satisfied and experience a greater deal of “unhappiness”.

And then there’s the quarter life crisis. But I’ll save that for another post.

Okja

Okja

A gentle giant and the girl who raised her are caught in the crossfire between animal activism, corporate greed and scientific ethics.

Starring: Tilda Swinton, Jake Gyllenhaal, An Seo Hyun
Director: Bong Joon Ho

I was really keen on watching this film as it has been receiving rave reviews. Even from Mark Kermode! However, I found it to be disappointingly ok. Definitely didn’t live up to the hype.

I felt like the movie couldn’t make up it’s mind on whether it was a comedy or a serious drama. It just seemed all over the place with contrasting bits of exposition and over the top characters. I really liked Tilda Swinton’s performance in this though.

Source: Wikipedia https://upload.wikimedia.org/wikipedia/en/f/f6/Okja.png

Thoughts on the movie:

Better written reviews:

  • https://assholeswatchingmovies.com/2017/06/29/okja/

    Yes, it’s a completely weird movie, one that can feel like a cartoon and a horror at the same time, that can make you laugh amid the darkest of scenes. I realize this movie won’t be for everyone, but I found it profoundly interesting. Tilda Swinton is excellent, and Gyllenhaal does something we’ve never seen from him before. But it’s Seo-Hyun Ahn who steals the show, her bond with Okja and her purity of heart that elevate this movie from fantasy to fable.

  • https://theviewingtank.wordpress.com/2017/07/06/movie-review-okja/

    Okja, just like its titular character, is an ungainly bizarre hybrid – one part family movie, one part action adventure, and one part dark satire. However it can also be said that this is what saves it from being another formulaic hallmark movie about an animal and her human. It’s a technically impressive movie with bold statements that are worth pondering about.

  • https://adcoluke.wordpress.com/2017/07/07/i-attempt-reviews-okja/

    It’s a genius film, with a very clever twist on a topic that is very relevant in today’s society. Everything about it is very well done, and every second is enjoyable. You will be shocked, upset, thrilled, and jumping out of your seat during Okja, and when a film can make you do all that, you know it’s good.