What is the metabolic syndrome?

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Obligatory disclaimer: I am not a medical doctor, and the content of this website was created for informational purposes only. Such content is not intended as a substitute for medical advice, treatment or diagnosis.

Out of all the topics and questions we’ve covered in this blog, this one seems to be the one most likely to be misunderstood. During the first series of posts in the Rebuttals to Fatlogic series we published a number of writings on metabolic damage, which we came to realize is nothing else but metabolic adaptation: as our body becomes smaller in size due to weight loss, it requires less energy to run. In this post, we’ll go over what metabolic syndrome is, how it is diagnosed, and its risks.

First, what is a syndrome?

Half the problem in understanding what metabolic syndrome is comes from knowing what a syndrome is. Essentially, a syndrome is a series of symptoms and medical signs that present themselves together and that are correlated to a particular disease or disorder. Those symptoms (a symptom is a deviation from normal function) and signs can be of a physical or mental nature, affecting the shape, size, and appearance of body parts as well as behavior.

So what is the metabolic syndrome?

From Cornier et al, the metabolic syndrome (known as MetS in the literature) is

a clustering of componnents that reflect overnutrition, sedentary lifestyles, and ressultant excess adiposity.

I like that definition, it’s short, sweet, and it’s bound to piss the fatlogicians off. Unfortunately, that definition does little for the average person, so let’s take a look at what the the NHS says

Metabolic syndrome is the medical term for a combination of diabetes, high blood pressure and obesity.

In our posts on high blood pressure and diabetes we learned that that it’s not like you just wake up one day with diabetes or that your life is going on as usual, but suddenly you trip and BOOM! you now have high blood pressure, those conditions tend to take some time to develop.

Furthermore, when it comes to diagnosing high blood pressure, diabetes and whether someone has metabolic syndrome or not, some guidelines are to be followed. When it comes to metabolic syndrome, several institutions have proposed similar, but not exactly equal, guidelines, and both Wikipedia and Cornier et al do a good job of presenting them. In this post, however, we’ll stick to the International Diabetes Federation’s (IDF) criteria for diagnosing metabolic syndrome.

Diagnosing metabolic syndrome

According to the International Diabetes Federation’s diagnosis criteria, for a person to be defined as having the metabolic syndrome they must have (I’d love to quote straight from the IDF, but I don’t know how make a list and a quote at the same time in WordPress)

  • Central obesity – defined as waist circumference with ethnicity specific values or if BMI is greater than 30 kg/m²*
  • Plus any two of the following four factors:
    • Raised triglycerides – greater or equal than 150mg/dL (1.7 mmol/L)
    • Reduced HDL cholesterol – less than 40 mg/dL (1.03 mmol/L) for males or 50 mg/dL (1.29 mmol/L) for females
    • Raised blood pressure – systolic blood pressure greater than 130 mmHg or diastolic blood pressure greater than 85 mmHg
    • Raised fasting plasma glucose – greater than 100 mg/dL (5.6 mmol/L) or being diagnosed with type 2 diabetes

* when it comes to specific ethnic values for waist circumference, it’s better to just look at the IDF’s guidelines. Personally, I find the BMI cutoff is a much quicker fail/pass criterion.

From the different literature reviews I’ve read about this subject, the real debate regarding the metabolic syndrome comes down to properly defining its diagnosis criteria. Different institutions place more importance to some factors over others and their criteria differ in that regard, but the evidence is clear when it comes down to the existence of the metabolic syndrome. Quoting from the IDF guidelines

All groups agreed on the core components of the metabolic syndrome: obesity, insulin resistance, dyslipidaemia ([blood lipid leves that are too high or too low]) and hypertension. However, the existing guidelines were either difficult to use or gave conflicting results when attempting to identify individuals with the metabolic syndrome in clinical practice.


IDF experts recognized that there was a stark need for a single, universally accepted diagnostic tool that is easy to use in clinical practice and that does not rely upon measurements only available in research settings.

Risks and complications from the metabolic syndrome

From the IDF guidelines,

With the metabolic syndrome driving the twin global epidemics of type 2 diabetes and CVD [cardiovascular disease] there is an overwhelming moral, medical and economic imperative to identify those individuals with metabolic syndrome early, so that lifestyle interventions and treatment may prevent the development of [type 2] diabetes and/or cardiovascular disease.

From what we’ve learned in our posts on hypertension and diabetes, developing metabolic syndrome is a terrible idea, but wait, there’s more. As Cornier el at state, nonalcoholic fatty liver disease can also be associated with the syndrome, as can polycystic ovarian syndrome, sleep apnea, and hypogonadism. Again, none of that is good.

In closing

Having covered high blood pressure, diabetes and now the metabolic syndrome, it’s clear that having any of those conditions is not a pleasant thing, so take care of yourself before it’s too late. If you liked this post and would like to see more content like it, check our page on Rebuttals to Fatlogic.

See you next week!