Rapid Weight Loss and Changes in Metabolic Rate
Wow! I just read a fascinating study directly related to rapid weight loss and metabolism. I hope you find it as interesting as I did!
In 2012, Darcy L. Johannsen and colleagues reported on the effects of rapid and massive weight loss, even when a large reduction in calories was accompanied by vigorous exercise. I’m going to summarize the study for you here:
1. All participants were severely obese, with an average body mass index of 49.4. (A body mass index of 30 or higher is considered obese.)
2. After 30 weeks of caloric restriction and vigorous exercise, the subjects lost an average of one third of their initial weight.
3. Even with vigorous exercise (at least 90 minutes a day, 6 days per week), not all of the subjects’ weight loss was due to the loss of fat. About 17% of the weight loss was due to the loss of fat-free mass (FFM), including muscle tissue.
4. Even with vigorous exercise, the subjects’ resting metabolic rate dropped significantly, and this wasn’t just due to a loss of weight. (A smaller person will generally have a lower resting metabolic rate than a larger person due to less body mass to maintain.) In other words, the drop in metabolic rate was too large to be explained by the amount of weight lost alone.
5. This drop in resting metabolic rate was due to a phenomenon called metabolic adaptation. The brain changes the amount of hormones it secretes, telling the body to slow down the rate of chemical reactions in response to a rapid loss in body weight.
6. The subjects who lost the most weight had the largest drop in resting metabolic rate.
7. The researchers cited other studies which suggest that this drop in resting metabolic rate will persist over time, requiring the subjects to continue with vigorous exercise and a reduction in calories to maintain their weight loss.
I was surprised that the subjects lost non-fat tissue, even while exercising an hour and a half to four and a half hours per day. Their bodies were unable to utilize only fat stores for energy when calories were severely restricted, so some non-fat tissue was lost, despite their exercise regime. I assume that this loss of non-fat tissue would have been even more marked if the subjects hadn’t been exercising and relied on caloric restriction alone.
The moral of the story–lose weight slowly, unless your doctor recommends rapid weight loss to manage a serious health condition. While it can be discouraging to see the numbers on the scale change ever so slightly, rapid weight loss, at least in this study with obese subjects, appears to wreak havoc with a person’s metabolic rate. This means that maintaining a weight loss that was achieved quickly will be very challenging, particularly if the drop in metabolic rate persists. It’s important to know, however, that this study used a relatively small amount of subjects (16), and that weight loss was extremely rapid. It’s quite likely that results would be different if the weight loss wasn’t so rapid.
I’m going to try to find credible research that looks at the effects of slow weight loss on metabolic rate and will post it as soon as I can. In the meantime, most experts seem to think that a weight loss of one to two pounds a week is the best way to preserve muscle mass and to avoid a large drop in a person’s resting metabolic rate.
If you want to read the entire article, click on this link.
Reference: Darcy L. Johannsen, Nicolas D. Knuth, Robert Huizenga, Jennifer C. Rood, Eric Ravussin, and Kevin D. Hall. “Metabolic Slowing with Massive Weight Loss Despite Preservation of Fat-Free Mass”, Journal of Clinical Endocrinology and Metabolism. 2012 July; 97(7), 2489-2496. Published online April 24, 2012. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3387402/ on Jan. 31, 2014.
Holly Trimble, MS, LPT
Disclaimer: This blog is for informational purposes only. Readers should discuss any specific health concerns with their physicians.
Good job on this article! I became interested in this content and have many of the same views as you. This is really good info.
Appreciate this post. Let me try it out.
Just wish to say your article is as amazing. The clearness to
your submit is simply great and that i can assume you are knowledgeable in this subject.
Fine with your permission let me to seize
your feed to keep updated with forthcoming post. Thank you a million and please continue the rewarding work.
Feel free to surf to my blog: face creams
I all the time emailed this blog post page to all my contacts, since
if like to read it then my links will too.
Here is my web page :: green coffee extract side effects
I’d like to thank you for the efforts you’ve put in writing this site.
I’m hoping to check out the same high-grade
content from you later on as well. In fact, your creative writing abilities has motivated me to get my very own site now
Feel free to visit my weblog; muscle rip x
Very good article. I definitely appreciate this website.
Here is my website … HT Rush Muscle
I don’t even know how I ended up here, but I thought this post was good.
I don’t know who you are but certainly you are going
to a famous blogger if you are not already Cheers!
Here is my website; Belle Complex – http://img.nhoxiu.com -
Hi there! This post couldn’t be written much better! Reading
through this post reminds me of my previous roommate!
He continually kept talking about this. I am going
to forward this article to him. Pretty sure he’s going to have a great
read. Thanks for sharing!
my homepage; http://garciniacambogiaelites.org/ (http://www.nsawt-khv.ru/)
Does your site have a contact page? I’m having a tough time
locating it but, I’d like to send you an email.
I’ve got some suggestions for your blog you might
be interested in hearing. Either way, great site and I
look forward to seeing it grow over time.
Visit my web site hypnosis For Weight loss
Your style is really unique compared to other folks I have
read stuff from. Thank you for posting when you’ve got the opportunity, Guess I will
just book mark this site.
My web blog: ways to build muscle
Woah! I’m really loving the template/theme of this site.
It’s simple, yet effective. A lot of times it’s tough to get that “perfect balance” between usability and
visual appearance. I must say that you’ve done a fantastic job with this.
Additionally, the blog loads extremely fast for me on Chrome.
Have a look at my web-site http://hghfuels.com/
Good way of telling, and good piece of writing to obtain facts about my
presentation topic, which i am going to deliver in college.
my page :: Домашняя страничка
Way cool! Some extremely valid points! I appreciate you writing this
article plus the rest of the website is also very good.
My homepage – Buy Green Coffee Fat Burn
Thanks for any other excellent post. Where else may anybody get that kind of information in such a perfect approach
of writing? I have a presentation next week, and I am
on the look for such information.