I am so tired of people pointing to the National Weight Control Registry (NWCR) as proof that people can and do lose a significant amount of weight and keep it off. Well, yes, a small percentage of people can do that – between 2% and 5% of people who diet keep the weight off for more than 5 years. That means 98-95% of the people can’t and don’t.
From the NWCR’s own website, here is what NWCR says it is:
“There are currently more than 5,000 members of the National Weight Control Registry, all of whom have lost significant amounts of weight and kept it off. These members lost the weight in a variety of ways and for a variety of reasons. Some have lost 30 pounds, some 130 pounds. Some have kept the weight off for one year, some for decades. What they all have in common, though, is a commitment to successful weight loss maintenance. These are the success stories of just a few of our many participants.” [Emphasis added.]
So to be a “success story” on the NWCR, you only have to keep the weight off for one year. I could find no statistics on the site or elsewhere that showed how many people on the Registry actually kept their weight off for 5 years or more.
The statistics provided on the site are as follows:
* Registry members have lost an average of 66 lbs and kept it off for 5.5 years.
* These averages, however, hide a lot of diversity:
** Weight losses have ranged from 30 to 300 lbs.
** Duration of successful weight loss has ranged from 1 year to 66 years!
** Some have lost the weight rapidly, while others have lost weight very slowly – over as many as 14 years.
NWCR is often said to have 10,000 (or more) members; insinuating that all 10,000 have successfully kept 30 pounds or more off. However, 10,000 is the number of participants being tracked. Those are people who enrolled in the study. This does not mean these people have continued to be NWCR “success stories”.
So we have at most 10,000 who have signed up for the study, out of which 5,000 are current members.
I could not find any explanation of why 10,000 are being tracked but there are only 5,000 current members – I don’t know if current members are only those people who continue to keep the weight off or if current members are simply the people who are continuing to be in touch with the NWCR. I sent an e-mail to NWCR, I called NWCR (got voicemail, left a message). I have never received a response.
Joanne Ikeda, MA, RD, who was one of the authors of a 2005 critique of NWCR, kindly responded to my inquiry that the answer to my question is “nobody knows”. However, the critique provided the following information:
http://www.sciencedirect.com/science/article/pii/S1499404606602479 (To see the full text you will have to purchase the article, which I did.)
“The results show that 72% of participants were above their baseline weight when reassessed at year 2 (n = 1630).
“According to a 1997 article, 629 women and 155 men (784 in total) enrolled in the NWCR had lost an average of 30 kg and maintained a required minimum weight loss of 13.6 kg for 5 years. However, in their 2003 article, only 465 subjects did not regain any weight from baseline to year 2. There is no mention of what happened to the missing 319 subjects who were labeled as ‘individuals successful at long-term maintenance of substantial weight loss’ in the 1997 publication. Finally, the researchers have not published any follow-up data on the 784 subjects enrolled in the NWCR since 1997.”
1997 study described above – http://www.ncbi.nlm.nih.gov/pubmed/9250100?dopt=Abstract
2003 study described above – http://www.ncbi.nlm.nih.gov/pubmed/14668267?dopt=Abstract
A blogger who registered with NWCR in 2011, provided the following information which she says she received from NWCR:
“Participants in the registry have lost an average of 72 pounds, and they have maintained the minimum weight loss of 30 pounds for an average of 5.7 years. But only 13% have maintained this minimum weight loss for 10 years.
”Few people (11%) recovered from even minor lapses of 3-5 pounds regained.” [Emphasis added by blogger]
Now, according to the Boston Medical Center, approximately 45,000,000 Americans diet each year.
So while there are possibly 5,000 to 10,000 members of NWCR (since 1994) who have been able to sustain weight loss, all this tells you is that these people exit. That is all it does.
So next time someone cites the NWCR as their “proof” that maintenance of significant weight loss is achievable for other than a few people – remember how small a group the members of NWCR are compared to the number of people dieting each year; and remember that NWCR DOES NOT SHARE ANYTHING WITH THE PUBLIC regarding members who regain weight.
NWCR is also often cited as being a source of information on behavior that results in successful long term weight loss. Actually, it is simply a source of behaviors implemented by a (small) group of people whose bodies happened to react to those behaviors with weight loss and weight maintenance. Yippee skippee for them.
So, once again, all together:
We do not know how to achieve long term significant weight loss for most people.
And if someone tells you NWCR proves different, you tell them from me – “Yeah, and my fat ass chews crackers too!”