[Paleopsych] NYT: Diet and Lose Weight? Scientists Say 'Prove It!'
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Tue Jan 4 21:21:13 UTC 2005
Diet and Lose Weight? Scientists Say 'Prove It!'
New York Times, 5.1.4
By GINA KOLATA
With obesity much on Americans' minds, an entire industry
has sprung up selling diets and diet books, meal
replacements and exercise programs, nutritional supplements
and Internet-based coaching, all in an effort to help
people lose weight.
But a new study, published today, finds little evidence
that commercial weight-loss programs are effective in
helping people drop excess pounds. Almost no rigorous
studies of the programs have been carried out, the
researchers report. And federal officials say that
companies are often unwilling to conduct such studies,
arguing that they are in the business of treatment, not
"In general, the industry has always been opposed to making
outcomes disclosures," said Richard Cleland, the assistant
director for advertising practices at the Federal Trade
"They have always given various rationales," Mr. Cleland
said, from "'It's too expensive,' to even arguing that part
of this is selling the dream, and if you know what the
truth is, it's harder to sell the dream." The study,
published in today's issue of Annals of Internal Medicine,
found that with the exception of Weight Watchers, no
commercial program had published reliable data from
randomized trials showing that people who participated
weighed less a few months later than people who did not
participate. And even in the Weight Watchers study, the
researchers said, the results were modest, with a 5 percent
weight loss after three to six months of dieting, much of
Advertisements for weight loss centers often make it seem
that success is guaranteed for anyone who really wants it.
They feature smiling, thin, healthy people - results, the
advertisements imply, of simply following the program.
Scientists, however, want something more. They would like
to see carefully controlled studies that follow program
participants over a couple of years and compare their
success with that of nonparticipants.
But that sort of study is almost never done, said Dr.
Thomas Wadden, director of the weight and eating disorders
program at the University of Pennsylvania and the lead
author of the new study.
It is not as if no one has asked the companies to conduct
such research, he and others said. About a decade ago, Dr.
Wadden, Mr. Cleland and others met with commercial weight
loss companies at the Federal Trade Commission to discuss
getting some solid data on the programs' effectiveness.
"We tried to come up with a set of voluntary guidelines
with the idea that these would be disclosures that weight
loss centers would make prior to consumers' signing on the
bottom line," said Mr. Cleland.
"At the end of the day we agreed to disagree on the issue
of outcomes disclosure. I was convinced that it could be
done, but it was not something the industry was going to
The F.T.C., he said, could not force companies to do the
Lynn McAfee, the director of medical advocacy for the
Council on Size and Weight Discrimination, was aghast at
"I don't understand how you can have a product you never
evaluate for effectiveness," Ms. McAfee said. "It was a
slap in the face to all people of size."
Still, patients and their doctors need information, Dr.
Wadden said. So he and his colleague, Dr. Adam Gilden Tsai,
collected what information they could on the prices, the
methods, and the success of nine commercial weight loss
programs, like Jenny Craig, eDiets and Optifast and
self-help programs, like Overeaters Anonymous.
The investigators looked at the data presented on company
Web sites, called the companies and searched medical
journals for published papers. In their review, they
included studies published from 1966 to 2003, finding 108
that assessed commercial programs. Of those, only 10 met
their criteria. For example, the studies had to have lasted
at least 12 weeks and to have assessed weight-loss outcomes
after a year.
Dr. Wadden said that even in that handful of studies,
hardly any of them reported data for everyone who enrolled
in the weight-loss programs. Most included only people who
had completed the programs, making the outcomes "definitely
best-case scenarios," he said.
The costs of commercial weight-loss programs can vary from
$65 for three months on eDiets to $167 for the same time in
Weight Watchers to more than $2,000 for a medically
supervised low-calorie diet.
"Given the lack of good comparative data, it may make sense
to try the cheaper alternatives first," Mr. Cleland said.
Other experts said that patients might want to forgo the
"Doctors could do as well as these programs" in helping
people lose weight, said Dr. George Blackburn, an obesity
specialist at Harvard Medical School, simply by counseling
people to diet and exercise.
He added, "Doctors can, ought to and are qualified to get
The Weight Watchers study, published in 2003 in The Journal
of the American Medical Association, involved 423 people
who weighed an average of 205 pounds. Half the participants
were randomly assigned to attend Weight Watchers meetings
and follow the program. The other half tried to lose weight
on their own. After two years, the participants in Weight
Watchers had lost an average of 6.4 pounds. The other group
had lost no weight. Neither group showed a change in blood
pressure, cholesterol, blood glucose or insulin.
"We found no such evaluations of Jenny Craig or L.A. Weight
Loss," Dr. Wadden and Dr. Tsai wrote.
Kent Coykendall, a vice president of strategic planning and
business development for Jenny Craig, said the company had
begun a randomized study of 70 people on the program. But
in the meantime, he said, Jenny Craig has the records of
tens of thousands of participants attesting to the fact
that they lost weight - "a plethora of real data on real
people in the real world under real circumstances," Mr.
In their study, Dr. Wadden and Dr. Tsai also looked at
programs, like Optifast, Health Management Resources and
Medifast, that provide participants with medical
supervision and a low-calorie diet - 800 to to 1500
calories per day. Patients who stay with these programs,
the companies say, can lose as much as 15 to 25 percent of
their weight in three to six months.
But the researchers found no randomized controlled trials
of their effectiveness. And the studies that were conducted
independently of the companies showed that people on the
low-calorie diets weighed about the same a year later as
people on conventional diets. In addition, the companies'
own reports found high dropout rates, with nearly half the
participants in an Optifast study dropping out in 26 weeks.
But Dr. Larry Stifler, the founder and president of Health
Management Resources, objected.
"Their criteria - one of the things they always like to see
- is randomized controlled trials," Dr. Stifler said. But
such studies, he said, are not feasible when a company is
offering a treatment.
"People can't be told they can either join the program or
be in a control group. That's not what this treatment is
about," he said.
Dr. Stifler said his company had data showing that patients
dropped large amounts of weight if they stuck with the
diet. When the company assessed patients three years later,
some had still kept the weight off. Much of that data has
not been published, Dr. Stifler said, but it has been
presented at professional meetings.
Robert Hallock, vice president and general counsel for
Medifast, also said his company had unpublished but
promising data. The company keeps track of thousands of
patients, he said, and "everyone knows that low-calorie
diets and structured programs get huge amounts of weight
As for Internet-based weight loss programs, the only study
Dr. Wadden and Dr. Tsai found was one that Dr. Wadden, Dr.
Leslie Womble and their colleagues conducted, using eDiets,
which provides clients with low-calorie recipes and foods.
They randomly assigned participants to use eDiets or a
standard behavioral weight-loss manual. They also provided
counseling and weigh-ins to all the participants. After a
year, the eDiet participants had lost 1.1 percent of their
weight while those using the manual had lost 4 percent.
Susan Burke, vice president of nutrition services at
eDiets, says the program has changed since 2001, when that
study was done. "It's more personalized and flexible," she
says, and clients who use the support programs and diet
Programs like Take Off Pounds Sensibly (TOPS) and
Overeaters Anonymous are free or charge only nominal fees,
but it is not clear how participants fare. Carol Trinastic,
a spokeswoman for TOPS, said the organization collected
data on weight loss. The most recent, from 2003, indicate
that members lost 1,271,466 pounds or 5.9 pounds per
But the modest and temporary weight losses with diet
programs are not a surprise, Dr. Wadden said, because no
one knows how to elicit permanent weight loss.
"I don't blame the diet programs. They're fighting
biology," Dr. Wadden said. "Even in the best of
circumstances, people will regain a third of what they lost
in one year and two-thirds in two years and they may be
back to base line in five years."
He added, "Weight loss is not for the fainthearted."
course, some people do lose weight and keep it off, often
succeeding after repeated attempts to diet, said Dr. Rena
Wing, a professor of psychiatry at Brown and a co-founder
of the National Weight Control Registry.
To be part of the registry, people must lose 30 pounds or
more, by any means, including surgery, and keep the weight
off for at least a year. If they regain, they remain in the
registry, Dr. Wing said. "Once you're in, you're in," she
In 10 years, the registry has enrolled 4,700 people. Most
gained back some weight, but very few gained back all they
lost, Dr. Wing said.
But there also are those who say they have tried and tried
to reduce, only to regain the weight they so painfully
lost. For many, weight loss is never really out of their
minds. Often, the fatter the person, the greater the
"Your whole life is a diet when you're overweight," said
Janet B. Forton, a Pennsylvania woman who finally had
weight-loss surgery last year after struggling her entire
life to lose weight. "You go to bed at night praying you
make the right choices the next day."
Why do so many people keep trying to lose weight when they
so often gain it right back again? Dr. Peter Herman and Dr.
Janet Polivy, psychologists at the University of Toronto,
say that just the idea of dieting may give people a
"It turns out that simply declaring you are going on a diet
makes you feel better," Dr. Herman said. "It seems to boost
people's spirits. They feel they are empowering themselves
and they are already imagining themselves as the new and
better selves, taking control of their lives."
Ms. McAfee has a different explanation.
"It is so
penalized to be fat in this society that it's an investment
in your future not to be fat," she said. "It you're an
ambitious person you'll do anything," and even if the lost
weight is regained, "you'll do it again and again."
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