Rachel Woods, University of Lincoln
How much does your weight really say about your health? Probably less than you think. You could eat your five-a-day, hit the gym regularly, have textbook blood pressure and cholesterol levels – and still be dismissed as “unhealthy” based on the number on the scale. Meanwhile, someone with a so-called “healthy” weight might be skipping meals, running on stress and caffeine, and rarely moving their body.
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We’ve been taught to equate thinness with wellness and excess weight with illness. But the science tells a more nuanced story – one where weight is just a single data point in a far more complex picture. So if weight alone doesn’t reflect how healthy we really are, what does?
Body weight is one of the most measured aspects of health. Society places huge emphasis on it, and criticism of a person’s weight is often framed as a health concern. So how much meaningful health information does weight actually offer?
Simply put, body weight measures exactly that – the total weight of a body. Changes in weight over time can give an indication of a person’s calorie intake. If they are gaining weight, they are eating more calories than they burn. If they are losing weight, they are burning more than they eat.
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It is perhaps more useful to consider the health information weight doesn’t give us. Important health indicators, such as cholesterol, blood sugar, blood pressure and heart rate are not visible on the scales.
Neither does weight reflect the quality of someone’s diet. A person could be eating plenty of fruit, vegetables and whole foods, getting the vitamins and minerals needed for good energy, bone strength and immune function. Or they might not. They might be eating mostly healthy fats, like those found in olive oil, nuts and fish, which are linked to better heart health. Or they may get their fat from processed foods, high in saturated and trans fats, which increase the risk of heart disease. They may be getting plenty of fibre to support digestion, regulate their blood sugar and maintain healthy cholesterol, or they may be getting very little. Weight alone reveals none of these important dietary details. https://www.youtube.com/embed/B9zhrxeYKYA?wmode=transparent&start=0
Weight also doesn’t accurately reflect how much body fat someone carries, or more importantly, where that fat is located. Visceral fat (which surrounds the internal organs) is linked to a higher risk of heart disease, type 2 diabetes and some types of cancer, whereas subcutaneous fat, found just beneath the skin, poses fewer health risks <link.
Weight doesn’t give details about how much exercise someone does, which improves health even if it doesn’t lead to weight loss. Nor does weight reflect other major influences on health, like sleep quality or stress.
All of these factors are harder to measure than body weight, and far less visible at first glance, but they provide a much more meaningful picture of someone’s health.
This is not to say that there is no association between weight and these factors, but the link is not clear cut. Details such as someone’s diet quality or their activity patterns cannot be found by simply looking at their weight.
At a population level, there is a clear association between higher body weight and increased risk of disease. For instance, studies show that people classified as overweight or obese using body mass index (BMI), which is a measure of weight relative to height, tend to have higher rates of cardiovascular disease, type 2 diabetes and certain types of cancer.
Some people who are classified as overweight or obese have healthy blood pressure, cholesterol and blood sugar levels. This is often referred to as “metabolically healthy obesity”. On the other hand, someone with a “healthy” body weight might have high visceral fat, poor diet quality, or a sedentary lifestyle – increasing their health risks, despite appearing thin. Terms like “Tofi” (thin outside, fat inside) or “skinny-fat” have emerged to describe this. https://www.youtube.com/embed/zG_ou7gzPwQ?wmode=transparent&start=0
These examples highlight how health cannot be judged accurately by weight alone. Someone eating a fibre-rich diet, high in vegetables, whole grains and healthy fats – all of which are linked to better health outcomes, might still fall into the “overweight” category, and be perceived as unhealthy simply because they eat more calories than they burn.
Conversely, a person eating a diet low in nutrients but not exceeding their calorie requirements may be considered a “healthy” weight. Which of these people would be viewed as healthy by society, and which by a doctor?
Why we think weight matters
So, why is so much emphasis put on a person’s weight? In truth, it probably shouldn’t be. However, it is a cheap and easy thing to measure, unlike blood tests, dietary assessments or body scans, which require more time, money and expertise. It’s not to say that more detailed tests are never carried out, but cost is usually a consideration.
Weight is also very visible. It is one of the few aspects of health that’s apparent to others at a glance. This makes it easy for society to pass judgement. But what is visible isn’t always what matters most. Societal ideas about what a “healthy” body looks like are deeply ingrained and not necessarily evidence based.
While losing weight as a result of healthy lifestyle modifications improves health, these modifications, such as increasing exercise and improving diet, have been shown to benefit health even if weight is not lost.
It has also been shown that the societal stigma surrounding obesity is not helpful in achieving weight loss, and can actually undermine it.
Therefore, if health really is the main concern, attention should shift away from weight as the primary focus and towards factors such as diet quality, physical activity, sleep and stress. Improvements in these areas can offer health benefits to people of all sizes.
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Rachel Woods, Senior Lecturer in Physiology, University of Lincoln
This article is republished from The Conversation under a Creative Commons license. Read the original article.