How the body fights for YEARS to restore dramatic weight loss caused by crash diets?
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- Dr. Kevin Hall examined 14 Biggest Loser contestants over six years
- He found their metabolisms slowed, making it harder to burn calories
- Also their levels of leptin, a hormone that stops hunger, dropped by half
- Nobody expected these conditions would continue for six years
- The body, he argues, will always try to return to its 'ideal weight'
- But the 'ideal weight' seems to go up by one or two pounds each year
In
the Fall of 2009, they were the idols of overweight couch potatoes
everywhere: the stars of weight-loss game show The Biggest Loser,
shedding thousands of pounds between them over 13 gruelling weeks.
But
in the six years since, almost all of them, including winner Danny
Cahill who shed a massive 239 pounds, have put the weight they'd lost
back on - some even ending up heavier than before.
And what science has discovered about their post-show failure has changed what we know about weight loss, The New York Times reported.
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Big winner:
Danny Cahill (pictured left, before his 2009 appearance on The Biggest
Loser, and right, after) lost 239lbs in 13 weeks on the show - but like
13 of the 14 contestants tested by scientists, he put weight back on
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The 14 contestants, all from season eight of the show, which still runs today, were monitored by Dr. Kevin Hall, a metabolism expert at the National Institute of Diabetes and Digestive and Kidney Diseases, one of the National Institutes of Health.
What
he found is that the human body will fight to restore weight lost in
crash diets - even over the course of many years - due to long-lasting
changes to how the body processes calories.
'It is frightening and amazing,' Dr. Hall told The New York Times, 'I am just blown away.'
Every person has a 'resting metabolism' which shows how many calories they burn when not exercising.
Prior to the show, even though all of the contestants were overweight, they had metabolisms that were normal for their size.
But
after the 13 weeks of intensive exercise they underwent for Biggest
Loser, Dr. Hall discovered, their resting metabolisms slowed
dramatically.
That
meant even though they were thinner, they were now burning off hundreds
fewer calories than someone of that size would be expected to.
The
doctors had expected this - what they didn't expect was that their
metabolisms would still be damaged six years later, and get slower and
slower with time.
Cahill,
for example, now burns 800 fewer calories a day at rest than doctors
would expect from looking at him. And of course, that makes it
increasingly hard to keep the weight off.
That,
at least in part, explains why, after going from 430 pounds before the
show to 191 pounds when he won, now weighs 295 pounds.
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Similar
things happened to other competitors: Rudy Pauls weighed 442 pounds
before the show and 234 pounds after, but had ballooned to 390 pounds by
2014.
That
year he had surgery on his digestive system to reduce weight again, and
now weighs 265 pounds. He now burns 516 fewer calories a year than
might be expected.
And
Sean Algaier, who started Biggest Loser at 444 pounds and dropped to
289 pounds, now weighs MORE than he did before, with a weight of 450
pounds and a metabolism that burns 458 fewer calories than it should.
The
problem, The New York Times reported, is that the human body appears to
have an 'ideal weight' - one it is easy to maintain - and will fight to
restore that weight, even when efforts are being made to burn it off.
Robert
Huizenga, the Biggest Loser's doctor, expected the contestants’
metabolic rates to fall, just not quite as far - and he questioned
whether the measurements made by Dr. Hall six years later were accurate.
However,
he did admit that keeping weight off is hard, and said that he advises
contestants to exercise at least nine hours a week and carefully control
their diets to keep weight down.
'Unfortunately,
many contestants are unable to find or afford adequate ongoing support
with exercise doctors, psychologists, sleep specialists, and trainers,
he said, 'and that’s something we all need to work hard to change.'
But
the long-term effects that Dr. Hall discovered weren't just about the
metabolism - weight loss also affected hormone production, he said.
Specifically, leptin - a hormone produced by the body that stops hunger cravings.
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Losses: This graph shows how four
contestants fought to lose weight - and how three ended up getting it
back. Rudy Pauls, the yellow line, weighed 390lbs when he had stomach
surgery in 2014; his weight dropped again
Slowdown: This graph shows how the
metabolisms of four contestants slowed down dramatically, causing them
to burn off far fewer calories per day than someone of their respective
weight ought to
Hormones: Arrows point to leptin
receptors in cells. The hormone leptin stops people from feeling hungry.
All contestants had nearly no leptin after the show, making them
ravenous, and only got half their leptin back later
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Before
the show, the contestants all had normal levels of leptin. Afterwards
they had almost none - which left them feeling permanently ravenous.
Those
leptin levels went up as the contestants put on weight, Dr. Hall said,
but only to about half the level they were at before.
That's left them with fierce cravings that must be fought to keep weight down.
Errin Egbert is the only one of the contestants tested whose weight is lower now than when she finished Biggest Loser.
Now
a fitness coach according to her Facebook profile, she went from 263
pounds to just under 176 on the show, and now weighs between 152 and
157. Her metabolism now burns 552 fewer calories than is expected for
her size.
She
told The New York Times that she can't let herself give in to the
cravings. 'What people don’t understand is that a treat is like a drug,'
she said.
'Two treats can turn into a binge over a three-day period. That is what I struggle with.'
In
a separate study at the University of Melbourne, Dr Joseph Proietto and
his colleagues studied leptin and four other hunger hormones in the
bodies of 50 overweight people who were asked to eat just 550 calories a
day.
They
lost weight dramatically, but put it back on afterwards - the result of
an increase in another hormone that makes people feel hungry.
'The body puts multiple mechanisms in place to get you back to your weight,' Dr. Proietto told The New York Times.
'The
only way to maintain weight loss is to be hungry all the time. We
desperately need agents that will suppress hunger and that are safe with
long-term use.'
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Hard
worker: Erinn Egbert (left before The Biggest Loser, right in 2015) was
the only one tested who kept the weight off. Her metabolism slowed,
burning 552 fewer calories than it should, and she struggles with
cravings
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According to Dr. Lee Kaplan, an obesity researcher at Harvard, the
body's 'ideal' weight is set in the brain - and the body will hold on to
any spare calories it can to keep at that weight, especially when
people are on a diet.
And to make things worse, that 'ideal weight' seems to creep up year by year.
According
to Dr. Michael Rosenbaum, an obesity researcher at Columbia University,
of the 900,000-1million calories eaten on average every year, most
people have 3,000-5,000 they don't burn off.
Per day, that's only one Starburst candy.
But
per year, that's an increase of one to two pounds. 'The cumulative
consequences over time can be devastating,' Dr. Rosenbaum said.
Dr.
David Ludwig, director of the New Balance Foundation Obesity Prevention
Center at Boston Children’s Hospital, who examined Dr. Hall's research,
told The New York Times said for most people losing weight purely by
changing their diet was impossible.
'There
are no doubt exceptional individuals who can ignore primal biological
signals and maintain weight loss for the long term by restricting
calories, he said.
'[But]
for most people, the combination of incessant hunger and slowing
metabolism is a recipe for weight regain - explaining why so few
individuals can maintain weight loss for more than a few months.'
