How much weight should you give to the number on the scales when it comes to good health? This has been hotly debated by experts, and HFG weighs in.
Weight, height, body mass index (BMI), waist circumference, waist-to-hip ratio… With so many measurements to determine if your weight falls within a healthy range, it’s no wonder you might think how much you weigh is the key indicator of good health.
But when did the quest for good health and wellbeing become so entangled with having a perfect figure or being a certain clothing size? There’s been a strong push recently towards the ‘you can be healthy at any size’ school of thought. And alongside this is a vocal band of health professionals arguing that the promotion of diets is unethical, and that BMI and weight alone is not enough to indicate a person’s health status. Read on to discover the latest science and what the medical experts make of it.
Many people assume they’re in good shape because their weight falls within a healthy range. Yet research suggests it’s possible to carry a lot of weight and still be 100 per cent healthy, or at least free of the health risks typically associated with a lot of weight gain.
One recent study concluded that as many as one in two who were classified as overweight by BMI were actually ‘metabolically healthy’. This term describes the absence of markers (high blood pressure, elevated cholesterol and insulin resistance) that increase the risk of certain conditions. For one in three whose BMI classified them as obese, it was the same story.
Leading obesity researcher Professor John Dixon is Head of Clinical Obesity Research at Melbourne’s Baker IDI Heart and Diabetes Institute. He recommends caution around this concept of ‘metabolically healthy’ obesity.
“The trouble is, people living with obesity can be metabolically normal now, but, unfortunately, we know they don’t tend to stay that way in the years ahead,” he explains.
Even if they do, the health risks associated with obesity can still exist. According to a University of Glasgow study, people with obesity who have a healthy metabolic profile are four times more likely to develop type 2 diabetes. They also have a significantly higher risk of having a heart attack, stroke and respiratory diseases.
A person’s health is much more nuanced than one single calculation
There’s also the fact that having a BMI in the healthy range doesn’t guarantee being metabolically healthy. In fact, research shows that up to a quarter of people with a healthy BMI have a higher risk of type 2 diabetes and heart disease. This is due to fat being stored in riskier areas of the body, such as around the stomach, and having other risk factors like high blood pressure, high cholesterol levels and altered insulin sensitivity.
Tiffany Petre is the director of the Obesity Collective based at the University of Sydney’s Charles Perkins Centre. She believes these findings reinforce the fact that BMI is not a diagnosis.
“It’s definitely not,” she asserts. “We certainly don’t agree that you should measure health based on BMI. A person’s health is much more nuanced than one single calculation, so BMI alone is not enough to indicate a person’s health status.”
Does BMI matter?
While bodyweight is not the only factor to determine good health, what about body mass index (BMI)? This is calculated by dividing your weight in kilos by your height in metres squared, and used to be the way of checking if your weight was healthy.
Research links a higher BMI to an increased risk of a number of diseases, including type 2 diabetes, heart disease and certain types of cancer. But BMI doesn’t distinguish between fat and muscle. This means people with a lot of muscle mass will often have a high BMI, even though their body fat is in the healthy range. BMI also doesn’t reflect where body fat is stored.
For this reason, your waist circumference measurement is now considered vital. In fact, some studies suggest that it alone is a more useful measurement. A waist size over 94cm for men and over 80cm for women is considered a potential health risk.
Do I need to lose weight?
According to the World Health Organization, 39 per cent of adults are overweight and 13 per cent are living with obesity, worldwide. The health risks associated with excess weight can be serious, so this figure begs the question: as a nation, do we need to shed a few kilos?
Louise Adams is president of Health At Every Size (HAES) Australia, which advocates for a weight-inclusive approach to health. This not-for-profit also pushes back against the need for ‘intentional weight loss’.
“At HAES, we don’t deny there are correlations between weight and an increased risk of certain health conditions,” says Louise. “In line with that, please note our name is ‘health’ at every size, not ‘healthy’ at every size.
“But we also know that dieting to lose weight not only doesn’t work, there’s a significant metabolic impact from ‘weight cycling’ [or yo-yo dieting], which is what happens to most people who are trying to lose weight,” Louise explains.
Food for thought
A range of factors aside from weight influences our health — from sleep quality and stress levels to alcohol intake, smoking status, physical activity and diet. In fact, the results of a 2020 study designed to identify whether BMI or a Mediterranean-style diet had the bigger influence on the risk of death suggest eating a healthy diet may be more important than how much you weigh.
The study researchers discovered that, while eating a Mediterranean diet helped compensate for the negative effect high BMI can have on longevity, people with BMIs in the healthy range who didn’t follow the diet actually had a higher risk of death than people in any other weight category who did follow the diet. A Mediterranean-style diet consists of eating a good variety of fresh fruit, vegetables, legumes, nuts, fermented dairy products, unrefined grains, fish and olive oil, while keeping intake of red meat and alcohol to a minimum.
Why dieting doesn’t work
Long-term studies show that most people can lose some weight on a diet, but the vast majority regain it — and sometimes more — within a few years. Keep repeating that yo-yo cycle, and you’re not only at risk of extra weight gain each time, due to the way dieting impacts metabolism, you also bump up your risk of heart disease and depression. One study found women who’d been through just one weight cycle were more likely to experience depression than those who hadn’t.
“So what we’re saying at HAES is, how about we provide healthcare without the side serving of weight loss,” Louise clarifies. “We encourage inclusive healthcare, so instead of focusing on shrinking bodies, it’s about taking care of diverse bodies. At the moment, we know that healthcare providers are trained to focus on weight. That means if you go to see a GP with an infected toenail and you have a BMI over 25, you’re going to be asked about your weight. And in some cases, depending on what you’re seeing your doctor for, you could even be refused healthcare based on your BMI. It’s wrong and it’s damaging,” she adds.
Professor Dixon agrees that achieving successful long-term weight loss is challenging. “It’s probably only five per cent of people who can lose weight by dieting and keep it off. And they’re likely to be the people who are not only obsessive about what they eat, but whose physiology allows them to be lighter.” But he also stresses that, for some, there’s no denying weight loss delivers health benefits. “We’re not saying everyone needs to lose weight. But sustained loss can have a profound effect on people carrying a lot of excess weight. And it doesn’t have to be a lot of weight: losing five to 10 per cent of body weight, and keeping it off, can have incredible health benefits and save lives.”
What’s the solution?
Professor Dixon recommends changing the conversation we’re having as a nation about obesity.
“At the moment, obesity is very much viewed by society — and sadly, most of our healthcare professionals, too — as being both the person’s fault and their responsibility to fix on their own. Both of which are just not true.
“For starters, at least 50 to 60 per cent of our propensity to be a certain weight is genetic. Then there’s the programming that occurs in utero before we’re even born. And there are so many things in our world that encourage obesity — everything from screen time to food supply.”
Petre agrees: “There’s this subconscious ‘understanding’ in society that obesity is 100 per cent within an individual’s control if they just made different choices. In that regard, obesity is treated very differently to any other health concern,” she says. “And it’s purely because of stigma.”
That stigma is both powerful and harmful.
“Weight stigma is a terrible thing,” adds Professor Dixon.
“It’s pervasive and discriminatory, and when it gets internalised, it reinforces that sense of guilt and failure, becoming a bit of a vicious circle.”
A shift in thinking
Petre says the Obesity Collective is pushing for a new approach. “As well as working towards solutions that address the social, environmental and biological factors that contribute to obesity, what we’d love to see for people who want to lose weight — acknowledging that it is a very personal choice and we’re not suggesting everyone ‘should’ lose weight — is the help of the healthcare sector,” she says. “People should have access to doctors who understand the evidence, science and complexity around obesity, rather than just being given lifestyle or behaviour change advice, then left to their own devices, as that’s setting them up to fail.
“Ultimately, the shift we’re trying to drive around how we think about, talk about and treat obesity is the same one that we’ve had about mental health over the last decade. We’ve still got a long way to go,” she concludes.
Article sources and references
- AIHW. 2020. Overweight and obesity. Accessed August 2021https://www.aihw.gov.au/reports/australias-health/overweight-and-obesity
- American Psychological Association. 2018. Why do dieters regain weight? Accessed August 2021https://www.apa.org/science/about/psa/2018/05/calorie-deprivation
- Bluher M. 2020. Metabolically healthy obesity. Endo Reviews. 41(3): 405–20. https://academic.oup.com/edrv/article/41/3/405/5780090
- Conus et al. 2007 Characteristics of metabolically obese normal-weight (MONW) subjects. Appl Physiol Nutr Metab. 32(1): 4–12. https://pubmed.ncbi.nlm.nih.gov/17332780/
- Deakin University. 2017. BMI is underestimating obesity in Australia, waist circumference needs to be measured, too. Accessed August 2021https://this.deakin.edu.au/self-improvement/bmi-is-underestimating-obesity-in-australia-waist-circumference-needs-to-be-measured-too
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- Ross et al. 2020. Waist circumference as a vital sign in clinical practice: a consensus statement from the IAS and ICCR Working Group on visceral obesity. Nature Reviews https://www.nature.com/articles/s41574-019-0310-7
- The University of Sydney. 2017. Waist circumference better indicator of early death than BMI. Accessed August 2021https://www.sydney.edu.au/news-opinion/news/2017/04/26/waist-circumference-better-indicator-of-early-death-than-bmi.html#:~:text=University%20of%20Sydney%20researchers%20have,than%20their%20Body%20Mass%20Index.
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