As a physical therapist, we address many issues related to injuries that can directly or indirectly affect an injury. One such topic is weight loss. Patients will often discuss their struggles or successes and ask for advice on what might be the best path to follow. This is a very challenging topic with no perfect answer for any one person and can be further complicated by emotional and medical aspects. Although we may not have all the answers, it is important to stay abreast of current literature and trends to help guide patients to the correct course.
This post was inspired by a recent article in the NY Times in which contestants on the Biggest Loser were tested 6 years post show for their metabolic rate. Many patients had read this article and we felt it warranted discussion on what current research may or may not be implying. The primary article was published in the Journal of Obesity and Morbidity and took place at the NIH(National Institute for Health). At this point, the majority of contestant had gained their weight back which corresponds to what occurs in the general population. Statics have shown only 1% of dieters can actually keep their weight off long term. What scientists have known is that the metabolism does slow down post diet but what occurs next was not highly researched.
This study although small in sample size showed that six years after losing large amounts of weight whatever weight the person was currently their metabolism was still at a deficient. So if they weighed 300 and lost 150lbs and then gained 60lbs back, their current metabolism was now 200 to 800 calories slower than a similar person at 210lbs. This presents a large challenge for people trying to keep weight off because their metabolism was not repairing. So a 210lb person who hypothetical needed 2000 calories to maintain, now needs1200 to maintain and then a 500 deficit on top of that just to lose just a pound a week. That is a very small amount of calories and makes the task even more challenging.
This factor alone would cause concern but they also found that these contestants had a deficit in leptin. Leptin is the hormone that stops us from bingeing. So now with this new body in order to maintain it, one requires less calories and is hungry. In fact, when the contestants started the show they had normal amounts of leptin, at the end of the show they had no leptin and 6 years later they have about half of what is expected. Leptin is not the only hormone that controls hungry but it does play a major role.
Controlling weight in an society with an abundant amounts of food that is sugar laden is a challenge under the best circumstances. Dr. Rosenbaum of Columbia University put it best,
“We eat about 900,000 to a million calories a year, and burn them all except those annoying 3,000 to 5,000 calories that result in an average annual weight gain of about one to two pounds,” he said. “These very small differences between intake and output average out to only about 10 to 20 calories per day — less than one Starburst candy — but the cumulative consequences over time can be devastating.” So although many people have been frustrated by this new information, others have taken a positive stance that this new study sheds light on where additional efforts needed to be focused in the field of weight loss.
References
http://onlinelibrary.wiley.com/doi/10.1002/oby.21538/
Fothergill, E., Guo, J., Howard, L., Kerns, J. C., Knuth, N. D., Brychta, R., Chen, K. Y., Skarulis, M. C., Walter, M., Walter, P. J. and Hall, K. D. (2016), Persistent metabolic adaptation 6 years after “The Biggest Loser” competition. Obesity. doi: 10.1002/oby.21538
