"The Biggest Loser" and Your Body's Weight Thermostat

This article, published Monday in the New York Times, has created quite a stir.  It profiles a study that followed 14 former contestants on the show, "The Biggest Loser."  The study found that over the course of six years, 13 out of the 14 contestants have regained some, most, or in some cases more than the weight they lost on the show.  Here's a figure from the article that gives a visual idea of how each of the contestants fared:


But the study's key finding was not the presumed failure of the contestants to maintain their weight loss.  Rather, it was the finding that each of the contestants' metabolic rates tanked when they lost weight, and this reduced metabolic rate persisted for years after the show.  In other words, it seemed their bodies were “defending” an internal weight set point.  They were able to defeat that set point for awhile (with millions watching), but eventually found it impossible to fight their bodies' natural urges.  And so they regained weight.  

This article highlights an emerging area of study in obesity science, that our bodies maintain an internal "weight thermostat."  For example, if your body's thermostat says "250 pounds", and you lose 70 pounds with diet and exercise, you will be left struggling against that 250-pound set point.  Through increased hunger, decreased energy, and likely other mechanisms, you will be pulled back up to 250 pounds.  This concept of a weight set point carries a number of profound implications, including:

  • Many diets may be successful in the short term, but almost all are doomed to fail in the long term.  (Isn't this exactly our experience?)
  • Weight regain after weight loss, or the struggle to lose weight in and of itself, has very little to do with will power.
  • The important question is not "How can I lose weight now?", but "How can I turn down my body's 'weight thermostat?'"

You may recall from my blog post in September 2015 that I am a firm believer in low carb diets, like Atkins.  This is because such diets directly address the underlying problem with weight for most people:  a chronically high insulin level.  Insulin is a hormone, made by the pancreas, that regulates blood sugar levels and fat metabolism.  Over time, our bodies can become resistant to insulin, locking us in a a cycle of ever increasing insulin levels in order to maintain steady blood sugar levels.  This cycle not only leads to weight gain, but can lead to type 2 diabetes.

Research is showing that insulin is also the primary hormone that "sets" our weight thermostat.  If we can turn down our insulin by decreasing our intake of carbohydrates (primarily), then we can quite possibly turn down the thermostat.  This means we can lose weight and, most importantly, maintain that weight loss.  (Research is also showing that cortisol, the stress hormone, has a role in setting the thermostat, too.)  

I recently read a great book, and I’d like to plug it now.  (In general, beware of doctors recommending books!  But bear with me just this once).  It’s called The Obesity Code:  Unlocking the Secrets of Weight Loss.  Published just two months ago, it was written by Jason Fung, M.D., a nephrologist who runs an obesity clinic in Toronto.  Dr. Fung addresses the very question of the “weight thermostat” in his book.  Let me give you the gist of his conclusions (for those of you that hate spoilers, just skip to the last paragraph of this post!).

  • Avoid sugar.
  • Limit your consumption of refined grains.
  • Don’t overdo protein.
  • Eat more healthy fats.
  • Eat more fiber.

Not rocket science, right?  But the details in the book are valuable, and each of his five points are nuanced and detailed.  Some questions posed by the book that I've been considering:  1) Is breakfast indeed the "foundational meal" of the day?, and 2) Does fasting have a place in healthy weight loss and maintenance?

I'll wrap up with news about CovenantMD.  We continue to grow!  People in our community are excited by the high-quality, accessible, low-cost care that Direct Primary Care offers.  Are you, or any friends or family, interested in hearing more?  We're holding a free information session on Saturday, May 21, from 10-11am at our office.  This is a chance to come kick the tires of CovenantMD, and find out more about the Direct Primary Care revolution.  And we'll have food and coffee!  RSVP to lancasterdpc@covenantmd.net.

Patrick Rohal, M.D. is a family doctor and founder of CovenantMD, a Direct Primary Care practice in Lancaster, PA.  He lives in Landisville with his wife, Lynn, and 3 rambunctious kids.