Just the other day I was “fortunate” enough to witness a delightful tête-à-tête centred on diets. There was a rather nasty current to the conversation with the conclusion being that the healthier (and therefore more successful diet) was that of the person who was the slimmer of the two. I wish this conversation was an isolated one and I wish this point of view was infrequently held however neither is the case.
For too long society has held the point of view that being overweight or obese meant you were always in poor health. This message has been promoted in part due to an image-obsessed society (fuelled by celebrities and the image obsessed health, fitness and beauty industry) and what I call sort-of-science. Sort-of-science is when there is some real science in the mix of a pile of pseudo-science. This is really dangerous as it looks and sounds legit but it’s not science at all and can push a dangerous or unhealthy message.
So is being obese actually the worst thing for our health? Let’s take a look at the science.
Last year, during my Masters, I was really fortunate to undertake a subject called Diet and Disease. This subject covered a number of medical conditions and the role of nutrition in their cause, prevention, management and potentially even reversal. My favourite condition covered was obesity as it highlighted the complexities of this condition. Sadly the mantra of “eat less move more” has completely reduced this condition into nothing more than a food and exercise disorder. But did you know that there are many factors linked to obesity and that obesity is an actual medical condition? Some of these factors include: age, gender, genetics, pregnancy, metabolic/endocrine factors, smoking status, socioeconomic status nutrition, physical activity and level of education[1-4]. It’s truly a far more complicated condition than people realise.
What’s interesting to me is that we accept that perfectly healthy people can get sick due to their genetics. We understand that the likes of type 1 diabetes, Crohn’s, some cancers etc. are caused by malfunctioning genes. We understand that perfectly healthy people can develop high blood pressure or anaemia because something is going wrong with a system in their body and likely genetic in origin (i.e. iron-deficiency anaemia runs in my mum’s family). We also accept that some people can get away with eating whatever they like and not exercising because they have “good genetics”. Yet when it comes to obesity, we cannot accept that there are cases when people are perfectly healthy but their body (i.e. their genetics) are working against them. There is a name for this. It is called cognitive dissonance. If perfectly healthy people can have malfunctioning genetics, which result in a medical condition, then why can’t perfectly healthy people develop obesity (which is a medical condition) due to genetics?
This is where I need to divert a moment and explain something. There are people who are obese because they have made poor lifestyle choices. You can’t eat McDonalds for breakfast, lunch and dinner and not exercise and then complain about being morbidly obese. That’s a no-brainer. The people I am discussing in this article are the ones who have been battling their weight since childhood or perhaps later on in life after the birth of a child. The ones who exercise and eat well but make no in-roads on their weight. The people who have been on diets forever and a day but continue to gain weight. The people who are otherwise healthy, but have a persistently high body fat percentage.
So the question then begs, is there such a thing as a healthy, obese person? I will discuss this concept in more detail in my next blog but for now, the short answer is yes. In fact there is a medical term – metabolically healthy obese individuals (MHOI) [5, 6]. So what does this mean?
When someone is considered to be metabolically healthy, they have normal markers such as blood pressure, a normal triglyceride to HDL ratio, normal insulin levels and normal blood glucose levels. Why are these markers so significant? Because they are markers for cardiovascular disease (CVD). This year alone, 33% of deaths in Australia will be due to this condition, which equates to almost 50 000 people. What really scary is that many people are completely unaware they have CVD, with their first warning being a heart attack or stroke. Sadly for many, this is the only warning they get. So how is it possible that someone can be completely unaware they’re so sick?
Well, just as there is a class of people who are obese but healthy, there is also a class of people who are normal weight but very unhealthy. These people are called metabolically obese normal weight individuals (MONWI) [5-8]. These people show signs of metabolic derangement (such as elevated glucose, insulin and blood pressure) but don’t know because these factors are initially asymptomatic. In addition to this, they are slim (or have a normal BMI) which means they are under the false premise they are healthy. Sadly they then believe that what they’re currently doing is working. This means they are not being encouraged to change their diet or start exercising by health professionals, when in fact they are walking heart attacks. It seems that medical professionals are generally only encouraging people to lose weight when they tip the BMI scale over 26. Otherwise, it’s business as usual.
Now don’t get me wrong, I am the first to say that excess body fat is not ideal BUT it needs to be in context. I am more concerned when I see body fat deposited on the abdomen than I am with body fat distributed evenly, subcutaneously (under the skin). In fact, there is a lower morbidity and morality associated with fat on the lower body. This is because the real danger is in a type of fat called visceral fat . This is the fat that is distributed around your organs (of particular concern around your heart and liver) . You cannot tell how much visceral fat someone has by looking at them. Just because someone has a high subcutaneous fat, does not mean that they also have a high visceral fat. The two are not mutually exclusive. So this also means that a low body fat does not equal a low visceral fat. The reason that visceral fat is incredibly dangerous, is because it is packed around organs and it leads to organ dysfunction. Increased fat around the heart can lead to heart arrhythmias, heart failure and heart attacks  whilst fat around the liver can promote non-alcoholic fatty liver disease (NAFLD) – a significant health concern and contributing factor to many other serious medical conditions. IN fact NAFLD is linked to insulin resistance, elevated blood glucose levels and high blood pressure – all markers of metabolic derangement.
The best way for the average person to determine visceral fat is via DXA or DEXA  – dual-x-ray absorptiometry assessment. This is why I encourage all my clients to have this assessed. In addition to DEXA, when I am assessing someone’s health, I look at a number of factors. I check blood pressure, I ask for blood tests (lipid profile, fasting insulin and glucose, liver function test, CRP, and potentially a few others depending on the individual), I measure their waist circumference and compare it to their height (waist to height ratio)  and I measure their body fat percentage using bioelectrical impedance. I also measure their current level of fitness and have a look at their dietary habits in conjunction with their relationship with food. These are just some of the measures that can be used to assess health but the point is that they are use in conjunction with each other and NEVER in isolation. Health is multi-factorial and must be assessed in a multi-factorial manner.
There is also some really important research that people need to know about if they are struggling to lose weight. There is one factor that you absolutely can control and offers significant protection against CVD. This is cardiorespiratory fitness. Barry et. al. (2014) concluded that the number risk factor for any cause of death was a low cardiorespiratory fitness . In fact so protective is cardiorespiratory fitness, that this study found that an obese individual who is fit, had almost an identical risk for any cause of death as someone who is a healthy weight and fit. See the table 1.
|Table 1: Relative Risk for Any Cause of Death |
This is not an isolated study. Professor Steven Blair (2009) concluded that the greatest threat to human health was physical inactivity  and there are many more studies like this. The graph below shows the magnitude of the risk of a low cardiorespiratory fitness (CRF), determined by Blair and colleagues. A low CRF absolutely dwarfs obesity as an ISOLATED risk factor yet the number one health intervention promoted to everyone is weight loss.
Figure 1.Attributable fractions (%) for all-cause deaths in 40 842 (3333 deaths) men and 12 943 (491 deaths) women in the Aerobics Centre Longitudinal Study. The attributable fractions are adjusted for age and each other item in the figure. *Cardiorespiratory fitness determined by a maximal exercise test on a treadmill.
So clearly this would indicate that getting fit would be an excellent primary health strategy but this is not happening. People are being told a) to lose weight (a good general recommendation but not the first thing they should focus on) and b) to do gentle physical activity. Let me tell you this – there is very little research on the safety of moderate intensity exercise vs. high intensity exercise and it is more than likely that HIT is safe for everyone (but that is another blog that I will write shortly). The number one strategy for anyone wanting to get healthy is to improve their fitness and unfortunately, gentle activity will not achieve this particularly well. Unfortunately, the public are receiving a watered-down, more palatable message about physical activity that is contributing to their health woes. Please note, there is absolutely nothing wrong with gentle exercise (it is very useful in the right setting) but there has to be some higher intensity exercise being done so that fitness is being improved. It is fitness that is protective. It is fitness that saves people’s lives!
So to summarise my key points:
- You can’t tell if someone is healthy by looking at them
- Being unfit is worse for you than being obese
- Obesity combined with fitness equals an almost normal risk for any cause of death
- It is hard to lose weight and keep it off – there are no guarantees around weight loss
- It is “easy” to get fit – everyone can get fit and it can be guaranteed
So to finish up, unless you can see inside someone’s body or you know what they’re eating and whether they’re fit, We MUST STOP JUDGING HEALTH BY APPEARANCES (I did it in capslock so you know I’m serious 😉 ). We are doing a disservice to everyone by being so focused on aesthetics. We marginalise those that are working their butts off to get healthy but are struggling with their weight and we lull those who are actually unhealthy, into thinking that they’re safe. That’s an absolute tragedy. Stay tuned for Part B later today.
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- Neeland, I., et al., Comparison of visceral fat mass measurement by dual-X-ray absorptiometry and magnetic resonance imaging in a multiethnic cohort: the Dallas Heart Study. Nutrition and Diabetes, 2016.
- Lee, C., et al., Indices of abdominal obesity are better discriminators of cardiovascular risk factors than BMI: a meta-analysis. Journal of Clinical Epidemiology, 2008. 61(7): p. 646-653.
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- Blair, S., Physical inactivity: the biggest public health problem of the 21st century. British Journal of Sports Medicine, 2009. 43(1): p. 1-2.