When I first heard about the Bulletproof Diet — the "revolutionary"
plan for weight loss — I tried to turn a blind eye. I really did.
But then, there were rumblings around the newsroom. "My Silicon
Valley Facebook friends are posting about it a lot," said one colleague.
Another wanted to know whether there was any science to the claims that
butter-laden coffee could actually help achieve a new level of mental
clarity. When the "cult" turned up in the New York Times, my editor said we should be writing about it, too.
I've
spent a lot of time thinking about diet and, unsurprisingly, came to
Bulletproof with a skeptical eye. But even I was blown away by how
science-y it is. The Bulletproof Diet is like a caricature of a bad
fad-diet book. If you took everything that’s wrong with eating in
America, put it in a Vitamix, and shaped the result into a book, you'd
get the Bulletproof Diet.
The book is filled with dubious claims based on little evidence
or cherry picked studies that are taken out of context. The author,
Dave Asprey, vilifies healthy foods and suggests part of the way to
achieve a "pound a day" weight loss is to buy his expensive,
"science-based" Bulletproof products.
But there's a silver lining: the Bulletproof Diet brings together in
one place everything that should make you skeptical of fad diets. It's a
teachable moment and its various offenses serve as a collection of
giant, red warning flags.
narrative. In this case, Asprey was a Silicon Valley investor who had
all the personal success he could have dreamed of but not enough energy
to enjoy it because, by his mid-20s, he weighed about 300 pounds.
So
he channeled his nerdiness to "hack" weight loss, investing $300,000 of
his money on research, travel, and experimentation. With this book,
he’s bringing the secret of easy and quick weight loss to the masses.
Even
without reading the book, you can be assured that however well-meaning
the plan may be, it's bunk. I'm sure the diet worked great for Asprey,
who looks very handsome on his book jacket. But every credible
researcher I have ever spoken to on diet — notably those who aren’t
selling books and products — has said that the one thing they have
learned is: there is no one best diet that works for everyone.
A bunch of studies, and studies of those studies (or meta research),
have shown that all diets — low fat, low carb, Weight Watchers, Atkins,
etc. — have about the same modest results in the long run, no matter
their macronutrient composition.
As I have written previously,
these findings from the literature should be liberating: they mean that
we’ve been sold this idea that if we just buy into one particular diet —
and purchase all its associated books and energy bars and health shakes
— we will walk the golden path to thinness. But science
(and experience) have shown us that that's not true. The researchers all
recommended simply cutting calories in a way you like and can sustain.
likely it is to fail. And make no mistake. The Bulletproof Diet is very
extreme. It's basically a very low-carb Paleolithic diet that emphasizes
saturated fat.
To become Bulletproof — "reclaiming energy
and focus" and "upgrading your life" — you need to cut your intake of
gluten and sugar, stop eating grains and legumes, and nearly eliminate
fruit because it's basically candy, according to Asprey.
As he
told me, "The Bulletproof Diet is a roadmap not a prescription," but the
roads he offers are so limited — and they begin with guzzling his brand
of butter coffee each morning and then fasting — that it's hard to
imagine how far one could reasonably stray and still get results.
No
one would quibble with the fact that we should all eat more vegetables
and less sugar. After a science-y explanation of the evidence for the
diet, Asprey rightly told me in an email, "There is no one
on earth who can win an argument saying that white flour or soy isolate
is better for you than steamed broccoli or a piece of salmon."
Most
people know that, but can't live on diets that rely on these foods
only, especially when they're based on expensive, branded versions of
these foods (more on that later).
"Bulletproof," claiming that his classification system is
science-driven.
By this categorization, raw kale, raw spinach,
pumpkin, hazelnuts, almonds, chickpeas, quinoa, and cantaloupe are
"suspect." Corn, soy, and raisins are toxic.
I asked Asprey about this ranking system, and he explained that it's based on the "inflammatory" properties of each food.
To
be clear, inflammation is real. You body mounts a localized
inflammatory response in reaction to injury, and researchers are now
trying to understand the role chronic inflammation plays in diseases
like cancer.
But the nutrition researchers I spoke to — and other actual science-based thinkers — have pointed out
that anti-inflammatory diets haven't been clinically validated. Now,
some of these diets are very similar to the Mediterranean way of
eating, which is linked with very good health outcomes. But to suggest
that we know with certainty that specific foods reduce inflammation in
people, and that has a specific health benefit, is far reaching at best
and outright misleading at worst.
is one best way to help people lose weight, and that is
eliminating inflammation." He said people who want to lose weight just
need to test out different foods, determine if they cause them to "feel food cravings and brain fog" and then eliminate those foods from their lives.
To
find out about the evidence behind this system, I looked at a bunch of
the citations for the claims that he makes about food. What I found was a
patchwork of cherry-picked research and bad studies or articles that
aren't relevant to humans. He selectively reported on studies that
backed up his arguments, and ignored the science that contradicted them.
Many of the studies weren't done in humans but in rats and mice.
Early studies on animals, especially on something as complex as
nutrition, should never be extrapolated to humans. Asprey glorifies
coconut oil and demonizes olive oil, ignoring the wealth of randomized trials
(the highest quality of evidence) that have demonstrated olive oil is
beneficial for health. Some of the research he cites was done on very
specific sub-populations, such as diabetics, or on very small groups of people. These findings wouldn't be generalizable to the rest of us.
Another journalist, writing in the UK Telegraph, perused through some of Asprey's citations and was similarly unimpressed:
Research at Tulane University, wasn't surprised by the poor quality of
the research he was using. There actually isn't a lot of good science in
humans on the health impact of specific foods, she explained. This kind
of research is extremely difficult to do. You'd need to get people to
substitute particular foods in their diets, and study them before and
after to learn about the effects of the dietary changes.
"But
these studies are usually done on a short-term basis and have small
sample sizes," she said. So they don't tell us much about the long-term
effects of eating particular foods and, because they have small sample
sizes, they don't always apply to the general population.
So you
should be very skeptical when Asprey — or anyone else — claims to have
found the "truth" about the harms of kale and nuts that others missed,
especially when they are based on single studies. As Matt Fitzgerald,
author of the book Diet Cults,
summed up: "If a diet guru says that something you've eaten your whole
life is toxic, change the channel — unless you're already dead."
Bulletproof-brand brew, butter and coconut oil — may be a novel
gimmick, the idea that people should eat a low-carb diet is not new.
And it has failed time and again in the past because, again, most people can't live like this, said obesity physician Dr. Yoni Freedhoff. He points
out, for example, that we tried restrictive, low-carb eating during the
Atkins boom. "In the year 2000, it is estimated that one in five
American households had one member who tried Atkins," he said. "If these
diets were sustainable we would still see one in five families on it
and we’d see improvements in the national waistline. We haven't seen
that."
While it may be true that folks who go on low-carb diets lose a little more weight in the short run, it’s also true
that these dieters have a very hard time adhering to them. "Any diet
that takes things to the extreme can often help you lose weight in the
short-term, but it is not sustainable," said Dr. Bazzano.
Asprey is right that the experiment of replacing fat with carbohydrates during the low-fat craze utterly backfired. Researchers now believe
that we should get more fat into our diets than they did 20 years ago.
But now Asprey seems to want to replace everything with fat. He swings
the pendulum in the other direction, suggesting that up to 70 percent
of one's calories come from this single macronutrient group. According
to him, fat is the best kind of fuel, and our bodies need lots of it for
optimal functioning.
Critics said Asprey goes too far with
the fat claims. "Now we know if you’re getting almost all of your
energy from any one of these macronutrients you need to think about
whether any one of those diets are healthy and sustainable," said Dr.
Bazzano, adding that the recommended intake of fat based on the best-available research is about 25 to 35 percent a day.
Dr. Freedhoff agreed. "Ultimately the issue I have got with this
style of diet — the issue with all low-carb diets — is not that they
can’t work or help but for the majority of people who go on them, it’s
not sustainable."
healthy are his own branded products: Bulletproof Brain Octane,
Bulletproof Chocolate Powder, Bulletproof Ghee, Bulletproof Whey, et
cetera.
Alarm bells should go off any time someone claims that
you should buy their expensive products for your diet. Especially when
the products come with miracle promises, like Asprey's Unfair Advantage,
which he suggests will help your body grow new mitochondria (the energy
powerhouses of the cells).
Lisa Dierks, a dietician at the Mayo
Clinic, said, "No matter what the diet is, when all of a sudden there
are all these things you’re encouraged to buy to make the diet more
successful, to me that’s always a flag."
She offered an
alternative: "If a patient came into my office and said, 'I want to
follow the Bulletproof Diet,' the first thing I would ask is 'What
attracts you to the diet?'" Then she tries to figure out a more
reasonable and sustainable approach, since, she said, she has seen
highly-restrictive fads fail patient after patient.
She likes to
remind her patients that what we know about healthy living is rather
simple and very difficult for diet gurus to make money off of: eat
mostly plants, do some exercise, don't smoke, and don't drink too much.
These recommendations have survived study after study, and worked for
generations of people all over the world. They're pretty much
bulletproof.
plan for weight loss — I tried to turn a blind eye. I really did.
Valley Facebook friends are posting about it a lot," said one colleague.
Another wanted to know whether there was any science to the claims that
butter-laden coffee could actually help achieve a new level of mental
clarity. When the "cult" turned up in the New York Times, my editor said we should be writing about it, too.
I've
spent a lot of time thinking about diet and, unsurprisingly, came to
Bulletproof with a skeptical eye. But even I was blown away by how
science-y it is. The Bulletproof Diet is like a caricature of a bad
fad-diet book. If you took everything that’s wrong with eating in
America, put it in a Vitamix, and shaped the result into a book, you'd
get the Bulletproof Diet.
The book is filled with dubious claims based on little evidence
or cherry picked studies that are taken out of context. The author,
Dave Asprey, vilifies healthy foods and suggests part of the way to
achieve a "pound a day" weight loss is to buy his expensive,
"science-based" Bulletproof products.
But there's a silver lining: the Bulletproof Diet brings together in
one place everything that should make you skeptical of fad diets. It's a
teachable moment and its various offenses serve as a collection of
giant, red warning flags.
"I have unlocked the single secret to weight loss!"
If that coffee isn't Bulletproof, you're in trouble. (Sean Gallup/Getty Images News)
Almost every fad diet-book starts with a compelling personal narrative. In this case, Asprey was a Silicon Valley investor who had
all the personal success he could have dreamed of but not enough energy
to enjoy it because, by his mid-20s, he weighed about 300 pounds.
So
he channeled his nerdiness to "hack" weight loss, investing $300,000 of
his money on research, travel, and experimentation. With this book,
he’s bringing the secret of easy and quick weight loss to the masses.
Even
without reading the book, you can be assured that however well-meaning
the plan may be, it's bunk. I'm sure the diet worked great for Asprey,
who looks very handsome on his book jacket. But every credible
researcher I have ever spoken to on diet — notably those who aren’t
selling books and products — has said that the one thing they have
learned is: there is no one best diet that works for everyone.
Bulletproof is basically a very low-carb, Paleolithic diet that emphasizes fat.
A bunch of studies, and studies of those studies (or meta research),
have shown that all diets — low fat, low carb, Weight Watchers, Atkins,
etc. — have about the same modest results in the long run, no matter
their macronutrient composition.
As I have written previously,
these findings from the literature should be liberating: they mean that
we’ve been sold this idea that if we just buy into one particular diet —
and purchase all its associated books and energy bars and health shakes
— we will walk the golden path to thinness. But science
(and experience) have shown us that that's not true. The researchers all
recommended simply cutting calories in a way you like and can sustain.
"You have to overhaul the way you eat completely!"
The researchers also warned, the more extreme a diet is, the morelikely it is to fail. And make no mistake. The Bulletproof Diet is very
extreme. It's basically a very low-carb Paleolithic diet that emphasizes
saturated fat.
To become Bulletproof — "reclaiming energy
and focus" and "upgrading your life" — you need to cut your intake of
gluten and sugar, stop eating grains and legumes, and nearly eliminate
fruit because it's basically candy, according to Asprey.
As he
told me, "The Bulletproof Diet is a roadmap not a prescription," but the
roads he offers are so limited — and they begin with guzzling his brand
of butter coffee each morning and then fasting — that it's hard to
imagine how far one could reasonably stray and still get results.
No
one would quibble with the fact that we should all eat more vegetables
and less sugar. After a science-y explanation of the evidence for the
diet, Asprey rightly told me in an email, "There is no one
on earth who can win an argument saying that white flour or soy isolate
is better for you than steamed broccoli or a piece of salmon."
Most
people know that, but can't live on diets that rely on these foods
only, especially when they're based on expensive, branded versions of
these foods (more on that later).
"The foods you and everyone you know eat regularly are toxic!"
These almonds might kill you. (HealthAliciousNess.com/Flickr)
In the Bulletproof Diet, Asprey ranks foods from "toxic" to "Bulletproof," claiming that his classification system is
science-driven.
By this categorization, raw kale, raw spinach,
pumpkin, hazelnuts, almonds, chickpeas, quinoa, and cantaloupe are
"suspect." Corn, soy, and raisins are toxic.
I asked Asprey about this ranking system, and he explained that it's based on the "inflammatory" properties of each food.
To
be clear, inflammation is real. You body mounts a localized
inflammatory response in reaction to injury, and researchers are now
trying to understand the role chronic inflammation plays in diseases
like cancer.
But the nutrition researchers I spoke to — and other actual science-based thinkers — have pointed out
that anti-inflammatory diets haven't been clinically validated. Now,
some of these diets are very similar to the Mediterranean way of
eating, which is linked with very good health outcomes. But to suggest
that we know with certainty that specific foods reduce inflammation in
people, and that has a specific health benefit, is far reaching at best
and outright misleading at worst.
He selectively reported on studies that backed up his arguments, and ignored the science that contradicted them.Still, Asprey went so far as to say: "There
is one best way to help people lose weight, and that is
eliminating inflammation." He said people who want to lose weight just
need to test out different foods, determine if they cause them to "feel food cravings and brain fog" and then eliminate those foods from their lives.
To
find out about the evidence behind this system, I looked at a bunch of
the citations for the claims that he makes about food. What I found was a
patchwork of cherry-picked research and bad studies or articles that
aren't relevant to humans. He selectively reported on studies that
backed up his arguments, and ignored the science that contradicted them.
Many of the studies weren't done in humans but in rats and mice.
Early studies on animals, especially on something as complex as
nutrition, should never be extrapolated to humans. Asprey glorifies
coconut oil and demonizes olive oil, ignoring the wealth of randomized trials
(the highest quality of evidence) that have demonstrated olive oil is
beneficial for health. Some of the research he cites was done on very
specific sub-populations, such as diabetics, or on very small groups of people. These findings wouldn't be generalizable to the rest of us.
Another journalist, writing in the UK Telegraph, perused through some of Asprey's citations and was similarly unimpressed:
The one about cerealDr. Lydia Bazzano, director of the Center for Lifespan Epidemiology
grains, for example, begins with a quote from the Bible and is written
by a man called Loren Cordain, otherwise known as the author of The
Paleo Diet, a health plan that involves eating only foods that were
available to humans during the Paleolithic (or caveman) era, and has
been widely discredited.
Another paper — "Switching from refined
grains to whole grains causes zinc deficiency" — is a report of a 1976
research project featuring a study group of just two people. A third
study - "Diets high in grain fibre deplete vitamin D stores" - is a 30
year-old study of 13 people.
A fourth - "Phytic acid from whole
grains block zinc and other minerals" – is based on a 1971 study of
people in rural Iran eating unleavened flatbread. Another is about
insulin sensitivity in domestic pigs.
In other words, the research upon which the Bulletproof Diet stands is not exactly cutting-edge.
Research at Tulane University, wasn't surprised by the poor quality of
the research he was using. There actually isn't a lot of good science in
humans on the health impact of specific foods, she explained. This kind
of research is extremely difficult to do. You'd need to get people to
substitute particular foods in their diets, and study them before and
after to learn about the effects of the dietary changes.
"But
these studies are usually done on a short-term basis and have small
sample sizes," she said. So they don't tell us much about the long-term
effects of eating particular foods and, because they have small sample
sizes, they don't always apply to the general population.
So you
should be very skeptical when Asprey — or anyone else — claims to have
found the "truth" about the harms of kale and nuts that others missed,
especially when they are based on single studies. As Matt Fitzgerald,
author of the book Diet Cults,
summed up: "If a diet guru says that something you've eaten your whole
life is toxic, change the channel — unless you're already dead."
"Stop eating an entire food group!"Carbs really aren't the enemy.
While the Bulletproof coffee — a blended mixture of specialBulletproof-brand brew, butter and coconut oil — may be a novel
gimmick, the idea that people should eat a low-carb diet is not new.
And it has failed time and again in the past because, again, most people can't live like this, said obesity physician Dr. Yoni Freedhoff. He points
out, for example, that we tried restrictive, low-carb eating during the
Atkins boom. "In the year 2000, it is estimated that one in five
American households had one member who tried Atkins," he said. "If these
diets were sustainable we would still see one in five families on it
and we’d see improvements in the national waistline. We haven't seen
that."
While it may be true that folks who go on low-carb diets lose a little more weight in the short run, it’s also true
that these dieters have a very hard time adhering to them. "Any diet
that takes things to the extreme can often help you lose weight in the
short-term, but it is not sustainable," said Dr. Bazzano.
Asprey is right that the experiment of replacing fat with carbohydrates during the low-fat craze utterly backfired. Researchers now believe
that we should get more fat into our diets than they did 20 years ago.
But now Asprey seems to want to replace everything with fat. He swings
the pendulum in the other direction, suggesting that up to 70 percent
of one's calories come from this single macronutrient group. According
to him, fat is the best kind of fuel, and our bodies need lots of it for
optimal functioning.
Critics said Asprey goes too far with
the fat claims. "Now we know if you’re getting almost all of your
energy from any one of these macronutrients you need to think about
whether any one of those diets are healthy and sustainable," said Dr.
Bazzano, adding that the recommended intake of fat based on the best-available research is about 25 to 35 percent a day.
Dr. Freedhoff agreed. "Ultimately the issue I have got with this
style of diet — the issue with all low-carb diets — is not that they
can’t work or help but for the majority of people who go on them, it’s
not sustainable."
"The best way to lose weight is by buying my special products!"
Remember the grapefruit diet? That seemed like a much more innocent time in dieting fads. (Photo by Ulrich Baumgarten)
In Asprey's food categorizations, many of the items that rank as mosthealthy are his own branded products: Bulletproof Brain Octane,
Bulletproof Chocolate Powder, Bulletproof Ghee, Bulletproof Whey, et
cetera.
Alarm bells should go off any time someone claims that
you should buy their expensive products for your diet. Especially when
the products come with miracle promises, like Asprey's Unfair Advantage,
which he suggests will help your body grow new mitochondria (the energy
powerhouses of the cells).
Lisa Dierks, a dietician at the Mayo
Clinic, said, "No matter what the diet is, when all of a sudden there
are all these things you’re encouraged to buy to make the diet more
successful, to me that’s always a flag."
She offered an
alternative: "If a patient came into my office and said, 'I want to
follow the Bulletproof Diet,' the first thing I would ask is 'What
attracts you to the diet?'" Then she tries to figure out a more
reasonable and sustainable approach, since, she said, she has seen
highly-restrictive fads fail patient after patient.
She likes to
remind her patients that what we know about healthy living is rather
simple and very difficult for diet gurus to make money off of: eat
mostly plants, do some exercise, don't smoke, and don't drink too much.
These recommendations have survived study after study, and worked for
generations of people all over the world. They're pretty much
bulletproof.
