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The BMI isn’t all its cracked up to be

<p>The obsession people have with weight is nothing new. But as the relationship between science and weight evolves, health professionals are increasingly advocating for a shift away from one of the most often used tools as an individual measure of health.</p> <div class="copy"> <p>The Body Mass Index – or BMI – has been used for the past half century as a standard measurement tool for weight and obesity. It’s calculated by dividing a person’s weight in kilograms by the square of their height in metres.</p> <p>This produces a figure which is indexed on a spectrum of weight ranges. A BMI below 18.5 is considered underweight, above 25 is overweight, and above 30 is obese.</p> <p>The latest episode of <em>Debunks</em>, a new podcast from Cosmos, investigates how useful the BMI actually is for assessing health.</p> <p>Health advocacy bodies, health insurers and government departments all make reference to the BMI as being a globally recognised standard for weight classification.</p> <p>Most – but not all – <a href="https://cosmosmagazine.com/health/bmi-overweight-obese-healthy-deaths/">acknowledge that the tool is imperfect</a>. Its <a href="https://cosmosmagazine.com/health/body-and-mind/body-mass-index-miscalculation/">simple arithmetic</a> is based on a system devised by 19th-century Belgian mathematician Adolphe Quetelet, who was an early pioneer of the social sciences and the use of data to understand human trends.</p> <p>The so-called ‘Quetelet Index’ was first described in 1832 as a means of trying to identify a calculation for the average man, first by conducting cross-sectional studies of infants and then adults.</p> <p>The need to consider weight as an indicator for health, mortality and morbidity, saw scientists trial several measurements before settling on Quetelet’s formula and rebranding it as the BMI in 1972.</p> <p>The problem? The BMI was largely based on studies of Anglo-Saxon populations. This is one of the biggest limitations often recognised by health groups. The Australian Department of Health, for instance, notes that a healthy BMI range is generally lower for people of Asian backgrounds, and higher for those of Polynesian backgrounds.</p> <p>But ethnicity isn’t the only limiting factor. Age and pregnancy status also play a part. Even athletes with more lean muscle (which weighs more than fat) might also find the standard BMI doesn’t capture their health status accurately.</p> <p>Diets and lifestyles have also shifted from the 19th century Belgian standard, and even from those of 50 years ago. Health professionals have long supported a shift away from the BMI being used as a rolled gold indicator of individual health, and medical professionals are beginning to take a wider view of patient health.</p> <p>“There has been a recent change in the position from the [US] National Academies of Nutrition and Dietetics surrounding BMI and there are shifts in the guidelines around BMI for medical diagnosis,” Dr Emma Beckett, a molecular nutritionist at the University of Newcastle, tells <em>Debunks</em>.</p> <p>The same goes for other measurements like waist-to-hip ratios and waist circumference. These metrics are often used by researchers conducting large population studies, but they don’t necessarily explain a person’s ‘health picture’.</p> <p>“Because we measure them in so many of our research studies, people mistakenly believe they are the most important markers of health and it’s just not true. Health is so much more complicated,” Beckett says.</p> <p>“The ‘normal’ [BMI] category is the one with the lowest health risks, but it doesn’t mean being in that category means you have no health risks and it doesn’t mean if you just get yourself into that category and change nothing else, there are no health risks.”</p> <p>On the latest series of Debunks, a podcast from Cosmos and 9Podcasts, find out how weight – and measurements like the BMI – are much more complicated than they might seem.</p> <p><iframe title="Weight: Should you care about your BMI?" src="https://omny.fm/shows/debunks/weight-should-you-care-about-your-bmi/embed" width="100%" height="180" frameborder="0"></iframe></p> <div><em>Image credits: Shutterstock</em></div> <div style="background-color: #f4f4f4; padding-top: 20px; padding-right: 20px; padding-bottom: 20px;"><em><a href="https://cosmosmagazine.com/health/body-and-mind/the-bmi-isnt-all-its-cracked-up-to-be/">This article</a> was originally published on <a href="https://cosmosmagazine.com">Cosmos Magazine</a> and was written by <a href="null">Cosmos</a>. </em></div> </div>

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The ultimate equation that proves how many calories you should be eating

<p><span style="font-weight: 400;">Everyone has been told that calorie-counting is the most effective way of lowering the scale and cutting the kilos.</span></p> <p><span style="font-weight: 400;">An average woman is said to require about 2000 calories per day to maintain a certain weight, and 1500 calories to lose almost half a kilo of weight per week. The average male is similar, but slightly raised: he needs 2500 calories to maintain, and 2000 to lose that half-kilo of weight per week. The general rule of thumb deemed by society is to exercise more and eat less.</span></p> <p><span style="font-weight: 400;">However, the math is not quite that simple. These rough estimations don’t consider numerous factors that would significantly sway the numbers: age, height, weight or activity levels. While you may think that frequent exercise is the best way to lose weight, it is not a transmutable technique for eating smart.</span></p> <p><span style="font-weight: 400;">Fortunately, calorie counting doesn’t have to be a total guessing game. Instead of using exercise as a mere safety net for your eating habits, use this elementary equation to pinpoint exactly how many calories you need per day.</span></p> <p><span style="font-weight: 400;">The calculation is called the Mifflin-St Jeor equation, a formula that has been shown to be the most accurate way of estimating calorie needs in numerous studies by the ADA (American Dietetic Association).</span></p> <p>Getting an idea of your basal metabolic rate (BMR)</p> <p><span style="font-weight: 400;">Begin by getting an idea of your basal metabolic rate (BMR).</span></p> <p><span style="font-weight: 400;">Your body must breathe, blink, grow cells and keep your heart beating on a daily basis.</span></p> <p><span style="font-weight: 400;">Staying alive isn’t an easy task, and it needs calories to do so. This number reflects an estimate of how many calories you would burn if you were to be hypothetically resting in a sedentary state for 24 hours.</span></p> <p><span style="font-weight: 400;">In other words, it represents the minimum amount of energy mandated to keep your body barely functioning, i.e. breathing and pumping blood.</span></p> <p><span style="font-weight: 400;">For men, the equation is as follows: 10 x weight (kg) + 6.25 x height (cm) – 5 x age (y) + 5. The equation is slightly different for women: 10 x weight (kg) + 6.25 x height (cm) – 5 x age (y) – 161.</span></p> <p><span style="font-weight: 400;">For example, if you were a 63kg, 30-year-old, 167cm woman, your BMR calculation would look like this: 10 x (63.5) + 6.25 x (167.6) – 5 x (30) – 161 = 1,371.5.</span></p> <p><span style="font-weight: 400;">Use this BMR number as the foundational reference point for safe weight loss. According to the Academy of Nutrition and Dietetics, your calories should never dip below 1,200. Doing so could mean your muscle mass starts decreasing, which means you won’t have enough energy to fuel daily activities.</span></p> <p><span style="font-weight: 400;">Now that we’ve figured out the bare minimum of calories your body demands, we can’t forget to account for the actual things you do throughout the day that burn these calories; walking to work, playing sports, doing yoga, or even watching TV all strip away those units of energy you consume.</span></p> <p><span style="font-weight: 400;">An easy way to do so is via this interactive calculator from the United States Department of Agriculture (USDA) that incorporates your activity level and BMR to give you an estimate of how much you should eat in order to maintain your current weight.</span></p> <p>The BMR rule of thumb</p> <p><span style="font-weight: 400;">If you want to do it yourself, here is a general map to follow. The final number is the recommended calorie consumption per day – tailored just for you:</span></p> <p><span style="font-weight: 400;">BMR x 1.2 for low intensity activities and leisure activities (primarily sedentary)</span></p> <p><span style="font-weight: 400;">BMR x 1.375 for light exercise (leisurely walking for 30-50 minutes 3-4 days/week, golfing, house chores)</span></p> <p><span style="font-weight: 400;">BMR x 1.55 for moderate exercise 3-5 days per week (60-70% MHR for 30-60 minutes/session)</span></p> <p><span style="font-weight: 400;">BMR x 1.725 for active individuals (exercising 6-7 days/week at moderate to high intensity (70-85% MHR) for 45-60 minutes/session)</span></p> <p><span style="font-weight: 400;">BMR x 1.9 for the extremely active individuals (engaged in heavy/intense exercise like heavy manual labor, heavy lifting, endurance athletes, and competitive team sports athletes 6-7 days/week for 90 + minutes/session)</span></p> <p><span style="font-weight: 400;">After all that, it’s important to note that this number isn’t necessarily something you should streamline your collective focus into. Although this does stand as the ideal formula to use as a guideline, weight loss boils down to more than just a number. Living your healthiest life doesn’t equate to shedding kilos, and obsessively counting calories can spiral one into an overly compulsive diet with dangerous downfalls.</span></p> <p><span style="font-weight: 400;">The induced stress can actually raise your cortisol levels, making it even harder for you to lose weight.</span></p> <p><span style="font-weight: 400;">In essence, be conscious of your healthy caloric intake, but it’s wiser to concentrate on what you’re eating than how much. Also, don’t forget the huge impact that WHEN you eat can have on your waistline.</span></p> <p><span style="font-weight: 400;">Your body knows best what it wants, so if it’s asking for fuel, indulge it, don’t spoil it.</span></p> <p><span style="font-weight: 400;">Written by Hana Hong. This article first appeared in </span><a href="https://www.readersdigest.com.au/healthsmart/diet/equation-proves-how-many-calories-you-should-be-eating?slide=all"><span style="font-weight: 400;">Reader’s Digest</span></a><span style="font-weight: 400;">. For more of what you love from the world’s best-loved magazine, </span><a href="http://readersdigest.innovations.com.au/c/readersdigestemailsubscribe?utm_source=over60&amp;utm_medium=articles&amp;utm_campaign=RDSUB&amp;keycode=WRA87V"><span style="font-weight: 400;">here’s our best subscription offer.</span></a></p> <p><img style="width: 100px !important; height: 100px !important;" src="https://oversixtydev.blob.core.windows.net/media/7820640/1.png" alt="" data-udi="umb://media/f30947086c8e47b89cb076eb5bb9b3e2" /></p>

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