“Obesity doesn’t kill.  Metabolic syndrome kills.”  

This quote from pediatric neuroendocrinologist, Dr. Robert H. Lustig transformed the way I practice pediatrics.   Let me explain how and why.

Throughout my medical training, I was inculcated with wrong notions about obesity being the problem.  For decades, many physicians like me, have been incorrectly taught that we could fix the obesity epidemic by simply telling our patients to eat less, exercise more.   We were indoctrinated into believing that it was all about calories and energy balance. This is certainly what I was taught, what I practiced, and yet, surprisingly, it never actually helped my patients!  Both personally and professionally, I considered myself a failure, as clearly, the medical advice I was doling out, wasn’t helping anyone improve their life.  

By the year 2010, I was a busy pediatric gastroenterologist in Seattle, WA.  While I loved seeing my patients, I’ll admit I was frustrated each time I diagnosed a child with non-alcoholic fatty liver disease (NAFLD).  At the time, NAFLD was misunderstood to be a complication of obesity.  Advising patients to lose weight by consuming fewer calories and exercising more only led to infuriating results!  

And then one day, I came across the work of pediatric neuroendocrinologist, Dr. Lustig, who was the first person to show me specifically how excessive intake of fructose is one of the primary drivers of NAFLD.   Hearing him speak, I felt like a light bulb suddenly went off in my head, and for the first time in my career, I felt excited and eager to see my next patient with NAFLD!  

From that day onwards, I have felt increasingly empowered and grateful each time I could help a child not only treat but reverse their NAFLD.  This is the difference between treating “obesity” and treating MetS.

MetS does NOT necessarily result from being obese or “fat”.  And it most certainly has nothing to do with the dietary intake of fat.

What is MetS? 

MetS is defined as having any/all of 4 specific problems, which result from the presence of fat being present in organs that have no business storing fat in the first place (so-called “ectopic” fat)!   MetS is the result of ectopic fat accumulation in organs like the liver, pancreas, muscle.  When fat builds up in these organs, normal cells are damaged, becoming dysfunctional and ultimately, dying.   The end result, metabolic dysfunction and increased death from diseases like Type 2 diabetes, heart attacks and strokes, not to mention dementia and cancer, leads to a whole host of other physical and emotional ailments along the way.

What are the 4 features that define MetS?

  1. Having an increased waist circumference (the so-called “apple vs pear shape”).
  2. High blood pressure.
  3. A high triglyceride: HDL ratio
  4. Abnormal blood glucose levels.

What is the risk of having MetS? 

Early death from cardiovascular disease is the biggest risk.  Someone with MetS is at an increased risk of stroke and Type 2 diabetes.

How prevalent is MetS?

MetS is a relatively new disease, but the prevalence is increasing at an alarming rate.  I had never heard of it growing up (I was born in 1972), or even while in medical school (1990s).  I barely heard about it during my pediatric residency (early 2000s) and in fellowship, I was still being taught that it was a disease mostly seen in adults, which resulted from morbid obesity.  Fast forward to 2021, and now at least 1 in 3 US adults have it, and globally, it’s estimated that 1 in 4 does.  What’s worse:  it now affects at least 15% of children. 

Similarly, pediatric NAFLD was basically unheard of prior to the 1980s.  And now it’s the most common chronic liver disease in the world, in both adults and children, not to mention, the 2nd leading cause of liver transplant in adults! 

Prior to the early 1980s, Type 2 diabetes was a rarity in children.  Now, 1 in 4 US teens is either diabetic or pre-diabetic.

Estimates say that by 2030, half of the US adult population will have MetS.

Who is at risk of MetS? 

We all are.  This is because most of today’s epidemic of MetS has been caused by an excessive intake of ultra-processed foods.  The food industry has led us to believe that obesity causes MetS (which it does not) and that excessive caloric intake causes obesity (which it does not).   In fact, as Dr. Lustig again beautifully recounts in his latest book, Metabolical, it’s not so much how much food we eat, or even what’s in the food, but what’s been done to that food, that has led to the MetS pandemic.

The children I meet today are often eating less than I did as a child yet gaining weight more rapidly.  This is due to additives like sugar, injected (on purpose, due to addictive properties) into most packaged foods, causing blood insulin levels to spike higher than they would, had these children been eating just real food.  And this spike in insulin subsequently leads to excessive and rapid weight gain.  It’s also this same disproportionate sugar intake that leads to NAFLD, which in turns causes our blood insulin to spike again!  It’s a vicious cycle that teaches me that the biochemical processes in our organs and cells precede obesity.   Fix the food system, and we’ll reverse MetS.  The obesity is merely a symptom of the disease.

The relationship between NAFLD and MetS (and most everything else!)

When we consume too much fructose (the molecule that makes sugar sweet), cells in the liver convert the excess fructose into fat, which then leads to NAFLD.  (A healthy liver has less than 5% fat.)

For too long during my medical career, I was practicing in a subspecialty silo.  I was seeing children who came in with a variety of gastrointestinal (GI) complaints (e.g., nausea, chronic stomach aches, bloating, diarrhea, constipation, etc.) and addressing these complaints in a vacuum, focused solely on the gut, and finding (or excluding) primary gut diseases (like Crohn’s disease or celiac disease or food allergies, etc.).   I can’t tell you the number of times I would even make a mental note about a child’s rapid weight gain (or a high BMI) while reviewing their records and growth curves in advance of a consultation, but then choosing to purposely ignore that, or at least not mention it during the actual visit, because I felt it was “not my responsibility” (delegating that to the primary care physician).  I also didn’t want to bring up what I figured (at that time, early in my career) was a wholly unrelated issue, separate from what they were seeing me about, namely, their GI symptoms.  

Now, I know the error of my ways!   As my practice and experience have evolved, so has my understanding of how MetS can present in a myriad of ways.  And I’ve come to better understand how dietary intake of mostly ultra-processed food causes systemic inflammation that not only can directly cause NAFLD/MetS but can also indirectly lead to a variety of complaints including nausea, diarrhea, and abdominal pain! 

I used to think that obesity caused NAFLD, and now I understand it’s the reverse.  It’s the biochemical changes (from excessive fructose intake) that lead to NAFLD (and subsequent insulin resistance) that then lead to obesity!  And since the hallmark of NAFLD is insulin resistance, which is also what drives MetS, the two conditions are basically one and the same.

No more practicing in a silo!  Each time I see a child with NAFLD, or any patient for that matter, even though I may not be that child’s primary care physician, I now realize that it is not only my duty but indeed, my moral obligation to bring up diet and nutrition and to review growth curves, especially when they show rapid weight gain.

Pediatricians are quite adept at assessing growth.  We consider the growth curve as the “5th vital sign” (in addition to the heart rate, respiratory rate, blood pressure, and temperature).  In fact, pediatricians are trained very well to always look out for weight loss or slow/poor weight gain.  Too many times to count, a referring pediatrician has called me after hours, requesting an urgent consultation for a child who is not growing adequately, worried about malnutrition, malabsorption, or “failure to thrive.”

However, ironically, all too often, and unfortunately, I see kids referred with GI symptoms or abnormal labs, following years of relatively rapid weight gain, which was not addressed in a timely manner.  My request is that we also consider a sudden and relatively rapid weight gain an equally urgent issue! 

Sadly, just as the food industry has created a system of new diseases that afflict today’s children differently compared to 30 or 40 years ago, pediatric health care professionals now need to think outside the traditional health care model and realize that “failure to thrive” and “malnutrition” are no longer the same conditions as we were taught, decades ago.  Understanding this difference is the key to understanding how to really promote health, wellness, and prevent disease.

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