Monday, March 2, 2009

95% of Statistics...

One of the worst things about being on a diet (or going through a lifestyle change, or slimming, or whatever it is you want to call watching what you eat!) is that inevitably someone just has to burst your bubble.

No matter how well you are losing weight, no matter how long you've kept it off, someone will eventually point out to you that "95% of all diets fail."

They usually have some sort of anecdotal evidence; "Yeah, my cousin, she lost 70 pounds, but you know, in three years, she'd gained all of it back and then some..."

Over the last year or so, that figure has haunted me. Particularly as I threw out or gave away my size 20's, 18's, 16s, etc. Will I just regain the weight? What am I doing this for? Isn't it worse to yo-yo diet and gain and lose the same weight over and over again?

The figure comes not from any kind of random sampling, but from a study of 100 patients treated for obesity at a nutrition clinic at New York Hospital in the 1950's. In 1959, its authors, Dr. Albert Stunkard and Mavis McLaren-Hume, published a paper in which they concluded, ''Most obese persons will not stay in treatment, most will not lose weight, and of those who do lose weight, most will regain it.''

That conclusion, Dr. Brownell of Yale said, has since become the most frequently quoted statement in obesity literature.

Dr. Stunkard, who is now a professor of psychiatry at the University of Pennsylvania, said the study was ''perfectly respectable'' for that period. ''The paper made a big impact because everybody thought obesity was pretty easy to treat,'' he said. ''This showed that, for whatever reason, it wasn't.''

But the study has little relevance to the current understanding of how to control weight, said Dr. Stunkard, who specializes in the treatment of obesity and eating disorders. The 100 patients in the study were ''just given a diet and sent on their way,'' he said. 1


So, this "dieting fact" that so many of us bump into on our journey is what... fifty years old, based on a very limited sampling size of 100 people who were just told "here's a diet, follow it." Yeah, I can see why that would probably not be successful.

More recent research has demonstrated that dieters find it challenging to maintain weight loss; however, it has refuted the 95% failure rate. In "Successful Weight Loss Maintenance" (Annual Review of Nutrition, vol. 21, no. 1, July 2001), Rena Wing and James Hill proposed defining "successful long-term weight loss maintenance as intentionally losing at least 10% of initial body weight and keeping it off for at least one year." Using this definition the investigators offered more favorable outcomes of weight-loss efforts. Wing and Hill reported that more than 20% of overweight or obese people can and do lose 10% or more of body weight and maintain the weight loss for more than a year. Analyzing data from the National Weight Control Registry, they also found that people who successfully maintained long-term weight loss—an average weight loss of 30 kg (66.14 lbs) for an average of 5.5 years—shared common behaviors that promoted weight loss and weight maintenance. These behavioral strategies included eating a diet low in fat, frequent self-monitoring of body weight and food intake, and high levels of regular physical activity. The investigators also posited that weight-loss maintenance may become easier over time because they observed that once weight loss had been maintained for two to five years, the chances of longer-term success were greatly increased.2
Ok, well, that's better. That means 20% or more people who have had successful weight loss will manage to maintain that weight loss. That's better. Even more encouraging is the posit that once the weight loss has been maintained for 2-5 years, chances of longer-term success are greatly increased.

Another problem with studies on weight loss is that it's difficult to track people over long term. The best place to get study subjects is either volunteers or through a medical program. Now keeping in mind that anyone who is seeing their doctor for help with their obesity problem probably has a really serious problem. I don't know about you, but I once didn't have a broken bone in my foot looked at by a doctor because I didn't think "it was particularly serious, I mean, what's he gonna do..." Likewise, most people would rather not discuss their weight with their doctor. (How many people do you know who have changed doctors, or just quit going to a doctor at all after being told they need to lose some weight?) (Which doesn't even begin to cover the fact that obesity is often cited as a reason to be denied health insurance, and I don't know very many people who can afford to see a doctor without it. And if you don't have insurance, your care is very minimal; make them stop bleeding and get the heck out of our hospital!)

Weight Watchers and Jenny Craig and other various national diet industries like to spout their figures, but obviously their sample is not random or typical, nor do they reveal numbers that they don't want you to see. (Remember what I told you Beth said about the "typical" weight watchers member attending meetings for 2 months and then vanishing?) Here's an interesting post about what Weight Watchers does, or does not, tell you. (Not, mind you, that this blog is at all biased, being a Fat Acceptance blog, but hey, the diet industry spins the numbers one way, you should see how they can be spun back...)

Similar studies tracked smokers who had been in a smoking cessation program, then tracked these patients after they had successfully completed the program, to see where they were, 5 years down the road.

Of those individuals contacted five years after the clinic, 17.8 per cent were not smoking.3
18%. You know, with an 82% failure rate, I find it amusing to notice that no one discourages people who are thinking about trying to quit with the same sort of depressing figures. "Why bother to quit smoking, you'll just go back to it, and probably smoke MORE than you used to..." I've never heard anyone say anything like that.

I think the important thing to remember is that statistics don't really mean anything. If you want to get a given result, you can redefine your parameters to get that result. It's not to say that statistics are completely useless, but at the same time, you should always consider who is paying for the study, what their parameters are, and what size of a test subject group they're working with.

1 New York Times, 95% Regain Lost Weight, Or Do They?

2 Diet and Myths Weight-Loss Lore and Controversies - Why Diets Fail

3 Five Year Follow Up of a Smoking Withdrawal Clinic Population.


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45+ and Aspiring said...

I never find statistics that applicable to my daily life. When I was a kid my mom used to quote to us, "Half of all kids whose parents get divorced end up divorced. So since there are only two of you (me and my sister)--one of you will end up divorced." Yeah, whatever. We weren't even married yet. (My sister's been married 27years and I've been married 15 years; so I think we're both doing OK.)

Studies also show that eating healthfully and exercising--that is living a lifestyle that is targeting weight loss--is healthier for you than not, even if you don't lose weight.

Also, people who quit smoking often have to quit several times before they quit for good.

I remind myself of these things.

I lost 60 lbs and kept it off for 6years, and then, alas, yes, I did gain it back plus. But it's not like I was mindless about doing it. And the fact that I lost it and kept it off for any time actually gives me more hope that I can do it again than if I had never done it at all.

So keep at it!

Cammy@TippyToeDiet said...

I have no partner link to offer you, but I will pop in to raise a guilty hand on that 'not going to the doctor' thing. But I'm over that now. :)

Excellent post, as always. I'm encouraged to know that in 1.5-4.5 years, this will get easier. One thing I'm sure of is that I will NOT become one of their numbers.

Have a great week!

Becky Fyfe said...

Excellent post!

And I am NEVER gaining any of this weight back!

Anonymous said...

I stopped talking to my doctor about weight loss when his FIRST "discussion" about it started, "Well, you need to lose a lot of weight. And obviously, at your age [mid-30s], a diet is a complete waste of our time-- you either don't want to or you've already tried and regained all the weight. So I recommend my gastric bypass surgery, I do a dozen of these a week...." (So... wait, doc, you'd recommend *major surgery* BEFORE any other options? Right, thanks, give me my clothes back, you incompetent ass.)

But as far as the statistics go... the most they can tell you is how the common denominator behaves under a specific set of circumstances. (After all, that's why they breed lab rats to be as generic as possible.) Let's look at smoking, for example... how long ago did *you* quit? And have you picked up a ciggy since?

Journo June aka MamaBear said...

OK, I think the big difference is between "going on a diet" and "making healthy lifestyle changes." Diets are usually ineffective because you feel deprived so as soon as it's over, you go back to old eating habits. By changing your eating and exercise habits, you make a lifestyle change that can last a lifetime.

You are doing an awesome job!
Path to Health

Anonymous said...

I ignore weight loss success statistics. I don't need any negative information telling me I can't do something. I've gotten rid of all the nay-saying from my life...that includes the scientific kind.

Anonymous said...

Looking at the crazy fad diets that people are always trying, I can see why the whole thing looks discouraging. Changing one's lifestyle to incorporate healthy food, not overeating, and exercise is a pain in the ass, and most people just want a quick fix. This weight losing stuff is hard slow work.

K @ Running Through Life said...

Excellent post!! Thanks!!!

Spring Girl said...

Those stats would be enough to make me quit a diet. But I agree that there is a difference between making healthy lifestyle changes and 'dieting'. At least I hope so!

Pubsgal said...

Came over from MizFit's blog to read this. Great info! I had no idea that's where the 95% figure came from.