The  answer to this  seemingly obvious question is  often confused by trying to define what  fat  and fit means.

Over the years the measurement of fat and indeed its distribution has raised some interesting  questions. I’m very aware of the muscular athletic awesome looking athlete who comes back from their annual medical having been told they are obese according to their BMI. These are people, who when their body fat is checked (using callipers or some sort of science fiction machine) are down into the enviable category! 

The next interesting “quickie” fat measure came when the discussion of abdominal obesity became fashionable the waist to hip ratio measurement was quick and easy and it certainly measured the tummy fat that showed.

Today, we should all be about visceral fat. But, It’s a hard thing to measure without a CT scan . The problem with visceral fat (the fat inside your visceral cavity, or around your organs) , is that skinny people can have visceral fat and that people with a big tummy don’t necessarily have visceral fat. It can sometimes be all subcutaneous!

Basically we have obvious fat and visceral fat.

Now we need to ask what is healthy or what is metabolically unhealthy According to Ortega (2012) .  If you crave the “metabolically unhealthy” crown, you must have one or more of these readings

• high blood pressure (≥130/85 mmHg)
• high blood triglycerides (≥150 mg/dL)
• low HDL “good” cholesterol (<40 and 50 mg/dL in men and women, respectively)
• high fasting blood sugar level (≥100 mg/dL)

Since the NHS actually started recording  the prevalence of obesity it was correlated with high blood pressure, high triglycerides, low good cholesterol and poor blood sugar. So it was quickly assumed that any overweight person would have these metabolically unhealthy markers. It wasn’t difficult to imagine the step to saying obesity causes them.

However, this is a great example that causation doesn’t necessarily mean causation.  Is it possible to be visibly overweight ( I know that’s terribly subjective, but work with me) but still have metabolically healthy readings ( good blood pressure, good  blood sugar).  

Ortega et al wrote ”The intriguing metabolically healthy but obese phenotype: cardiovascular prognosis and role of fitness ” 

They ran some tests using BMI and the 4 health markers and noted (i) metabolically healthy but obese individuals have a higher fitness level than their metabolically abnormal and obese peers; (ii) after accounting for fitness, metabolically healthy but obese phenotype is a benign condition, in terms of cardiovascular disease and mortality. this led to these conclusions (i) Higher fitness should be considered a characteristic of metabolically healthy but obese phenotype. (ii) Once fitness is accounted for, the metabolically healthy but obese phenotype is a benign condition, with a better prognosis for mortality and morbidity than metabolically abnormal obese individuals.

• “Metabolically healthy” obese participants had a better baseline fitness level on the treadmill test compared with “metabolically abnormal” obese participants (adjusting for age, sex, examination year, smoking and alcohol consumption, and when using either BMI or body fat percentage to define obesity). The difference was the same for men and women.
• “Metabolically abnormal” obese participants had significantly increased risk of dying from any cause during follow-up compared with “metabolically healthy” obese participants (adjusting for confounders and using either BMI or body fat percentage to define obesity).
• When looking at cardiovascular disease outcomes, “metabolically abnormal” obese participants only had increased risk of a fatal or non-fatal cardiovascular disease event compared with “metabolically healthy” obese participants when using body fat percentage to define obesity. There was no difference in risk when using standard BMI definitions.
• “Metabolically healthy” obese participants had no difference in risk of dying from any cause, or of fatal or non-fatal cardiovascular disease events compared with “metabolically healthy” normal-weight or fat participants.

On a narrow set of  health criteria and dubious “obesity’ assessments it’s quite possible to argue that you can be fat and fit!  However, over the years more concern has been raised about where your fat is . Research has indicated,visceral fat may be doing something  far more nasty. 

 “Visceral Fat Adipokine Secretion Is Associated With Systemic Inflammation in Obese Humans” 2007 concluded “that visceral fat is an important site for IL-6 secretion ( an inflammation causing thing) and provide a potential mechanistic link between visceral fat and systemic inflammation in people with abdominal obesity”. So there is an interesting line of experiments that indicate that visceral fat could be there, releasing nasty stuff.

The interesting thing is that you can be quite skinny and still have visceral fat and you can be obese and have no visceral fat. So based on some current evidence and where you fat is  you can be both  visibly fat and fit and skinny and ill!

(Update added 4th August 2020) However, it seems that science gallops on on! There are an increasing number of reports that suggest any sort of obesity is bad for your health. The above article looked at the narrow proposition that you can have “markers” of fitness and still be overweight. The clear answer is yes.

However there are other markers. Things like Adipokines, (which can be either pro or anti inflammatory ) It seems that the fatter you are, the more pro inflammatory they become. Which is bad.

So watch out for the next article in this series that will probably be “Can you be fat and healthy”