O fim da guerra à gordura – reportagem da revista TIME

Segue, abaixo, a íntegra da reportagem de capa da revista TIME dessa semana, encerrando o ciclo de 30 anos de orientação nutricional equivocada.

P.S.: A versão traduzida está aqui: http://www.paleodiario.com/2014/06/revista-time-terminando-guerra-gordura.html

Ending the War on Fat

Bryan Walsh

For decades, it has been the most

vilified nutrient in the American diet.

But new science reveals fat isn’t

what’s hurting our health



The taste of my childhood was the taste

of skim milk. We spread bright yellow

margarine on dinner rolls, ate low-fat

microwave oatmeal flavored with apples

and cinnamon, put nonfat ranch on our

salads. We were only doing what we were

told. In 1977, the year before I was born,

a Senate committee led by George

McGovern published its landmark

“Dietary Goals for the United States,”

urging Americans to eat less high-fat red

meat, eggs and dairy and replace them

with more calories from fruits, vegetables

and especially carbohydrates.

By 1980 that wisdom was codified. The U.S. Department of Agriculture (USDA) issued

its first dietary guidelines, and one of the primary directives was to avoid cholesterol

and fat of all sorts. The National Institutes of Health recommended that all Americans

over the age of 2 cut fat consumption, and that same year the government announced

the results of a $150 million study, which had a clear message: Eat less fat and

cholesterol to reduce your risk of a heart attack.

The food industry–and American eating habits–jumped in step. Grocery shelves filled

with “light” yogurts, low-fat microwave dinners, cheese-flavored crackers, cookies.

Families like mine followed the advice: beef disappeared from the dinner plate, eggs

were replaced at breakfast with cereal or yolk-free beaters, and whole milk almost

wholly vanished. From 1977 to 2012, per capita consumption of those foods dropped

while calories from supposedly healthy carbohydrates increased–no surprise, given that

breads, cereals and pasta were at the base of the USDA food pyramid.

We were embarking on a “vast nutritional experiment,” as the skeptical president of the

National Academy of Sciences, Philip Handler, put it in 1980. But with nearly a million

Americans a year dropping dead from heart disease by the mid-’80s, we had to try

something.

Nearly four decades later, the results are in: the experiment was a failure. We cut the fat,

but by almost every measure, Americans are sicker than ever. The prevalence of Type 2

diabetes increased 166% from 1980 to 2012. Nearly 1 in 10 American adults has the

disease, costing the health care system $245 billion a year, and an estimated 86 million

people are prediabetic. Deaths from heart disease have fallen–a fact that many experts

attribute to better emergency care, less smoking and widespread use of cholesterol-
controlling drugs like statins–but cardiovascular disease remains the country’s No. 1

killer. Even the increasing rates of exercise haven’t been able to keep us healthy. More

than a third of the country is now obese, making the U.S. one of the fattest countries in

an increasingly fat world. “Americans were told to cut back on fat to lose weight and

prevent heart disease,” says Dr. David Ludwig, the director of the New Balance

Foundation Obesity Prevention Center at Boston Children’s Hospital. “There’s an

overwhelmingly strong case to be made for the opposite.”

But making that case is controversial, despite the evidence to support it. The vilification

of fat is now deeply embedded in our culture, with its love-hate relationship with food

and its obsession over weight. It has helped reshape vast swaths of agriculture, as acre

upon acre of subsidized corn was planted to produce the sweeteners that now fill

processed foods. It has changed business, with the market for fat replacers–the artificial

ingredients that take the place of fat in packaged food–growing by nearly 6% a year. It’s

even changed the way we talk, attaching moral terms to nutrients in debates over “bad”

cholesterol vs. “good” cholesterol and “bad” fat vs. “good” fat.

All of this means the received wisdom is not going to change quietly. “This is a huge

paradigm shift in science,” says Dr. Eric Westman, the director of the Duke Lifestyle

Medicine Clinic, who works with patients on ultra-low-carb diets. “But the studies to

support it do exist.”

Research that challenges the idea that fat makes people fat and is a dire risk factor for

heart disease is mounting. And the stakes are high–for researchers, for public-health

agencies and for average people who simply want to know what to put in their mouth

three times a day.

We have known for some time that fats found in vegetables like olives and in fish like

salmon can actually protect against heart disease. Now it’s becoming clear that even the

saturated fat found in a medium-rare steak or a slab of butter–public-health enemies

Nos. 1 and 2–has a more complex and, in some cases, benign effect on the body than

previously thought. Our demonization of fat may have backfired in ways we are just

beginning to understand. When Americans cut back, the calories from butter and beef

and cheese didn’t simply disappear. “The thinking went that if people reduced saturated

fat, they would replace it with healthy fruits and vegetables,” says Marion Nestle, a professor of nutrition, food studies and public health at New York University. “Well,

that was naive.”

New research suggests that it’s the overconsumption of carbohydrates, sugar and

sweeteners that is chiefly responsible for the epidemics of obesity and Type 2 diabetes.

Refined carbohydrates–like those in “wheat” bread, hidden sugar, low-fat crackers and

pasta–cause changes in our blood chemistry that encourage the body to store the

calories as fat and intensify hunger, making it that much more difficult to lose weight.

“The argument against fat was totally and completely flawed,” says Dr. Robert Lustig, a

pediatrician at the University of California, San Francisco, and the president of the

Institute for Responsible Nutrition. “We’ve traded one disease for another.”

The myopic focus on fat has warped our diet and contributed to the biggest health crises

facing the country. It’s time to end the war.

The Fat Man

We have long been told that fewer calories and more exercise leads to weight loss. And

we want to believe that science is purely a matter of data–that superior research will

always yield the right answer. But sometimes research is no match for a strong

personality. No one better embodies that than Dr. Ancel Keys, the imperious

physiologist who laid the groundwork for the fight against fat. Keys first made his name

during World War II, when he was asked by the Army to develop what would become

known as the K ration, the imperishable food supplies carried by troops into the field. It

was in the following years that the fear of heart disease exploded in the U.S., driven

home by President Dwight Eisenhower’s heart attack in 1955. That year, nearly half of

all deaths in the U.S. were due to heart disease, and many of the victims were seemingly

healthy men struck down suddenly by a heart attack. “There was an enormous fear

overtaking the country,” says Nina Teicholz, author of the new book The Big Fat Surprise.
“The heart-disease epidemic seemed to be emerging out of nowhere.”

Keys had an explanation. He posited that high levels of cholesterol–a waxy, fatlike

substance present in some foods as well as naturally occurring in the body–would clog

arteries, leading to heart disease. He had a solution as well. Since fat intake raised LDL

cholesterol, he reasoned that reducing fat in the diet could reduce the risk of heart

attacks. (LDL cholesterol levels are considered a marker for heart disease, while high

HDL cholesterol seems to be cardioprotective.) In the 1950s and ’60s, Keys sought to

flesh out that hypothesis, traveling around the world to gather data about diet and

cardiovascular disease. His landmark Seven Countries Study found that people who ate

a diet low in saturated fat had lower levels of heart disease. The Western diet, heavy on

meat and dairy, correlated with high rates of heart disease. That study helped land Keys

in 1961 on the cover of TIME, in which he admonished Americans to reduce the fat

calories in their diet by a third if they wanted to avoid heart disease. That same year,

following Keys’ strong urging, the American Heart Association (AHA) advised

Americans for the first time to cut down on saturated fat. “People should know the

facts,” Keys told TIME. “Then if they want to eat themselves to death, let them.”

Keys’ work became the foundation for a body of science implicating fat as a major risk

factor for heart disease. The Seven Countries Study has been referenced close to 1

million times. The vilification of fat also fit into emerging ideas about weight control, which focused on calories in vs. calories out. “Everyone assumed it was all about the

calories,” says Lustig. And since fat contains more calories per gram than protein or

carbohydrates, the thinking was that if we removed fat, the calories would follow.

That’s what Keys, who died in 2004, believed, and now it’s what most Americans believe

too. But Keys’ research had problems from the start. He cherry-picked his data, leaving

out countries like France and West Germany that had high-fat diets but low rates of

heart disease. Keys highlighted the Greek island of Crete, where almost no cheese or

meat was eaten and people lived to an old age with clear arteries. But Keys visited Crete

in the years following World War II, when the island was still recovering from German

occupation and the diet was artificially lean. Even more confusing, Greeks on the

neighboring isle of Corfu ate far less saturated fat than Cretans yet had much higher

rates of heart disease. “It was highly flawed,” says Dr. Peter Attia, the president and

director of the Nutrition Science Initiative, an independent obesity-research center. “It

was not on the level of epidemiology work today.”

Keys’ unshakable confidence and his willingness to take down any researcher who

disagreed with him was at least as important as his massive data sets. (When the

biostatistician Jacob Yerushalmy published a 1957 paper questioning the causal

relationship between fat and heart disease, Keys responded sharply in print, claiming

that Yerushalmy’s data was badly flawed.) Keys’ research also played into a prevailing

narrative that Americans had once eaten a largely plant-based diet before shifting in the

20th century to meals rich in red meat. Heart disease followed, as if we were being

punished for our dietary sins.

The reality is that hard numbers about the American diet are scant before midcentury

and all but nonexistent before 1900. Historical records suggest Americans were always

voracious omnivores, feasting on the plentiful wild game available throughout the

country. In his book Putting Meat on the American Table, the historian Roger Horowitz

concludes that the average American in the 19th century ate 150 to 200 lb. of meat per

year–in line with what we eat now.

But the antifat message went mainstream, and by the 1980s it was so embedded in

modern medicine and nutrition that it became nearly impossible to challenge the

consensus. Dr. Walter Willett, now the head of the department of nutrition at the

Harvard School of Public Health, tells me that in the mid-1990s, he was sitting on a piece

of contrary evidence that none of the leading American science journals would publish.

“There was a strong belief that saturated fat was the cause of heart disease, and there was

resistance to anything that questioned it,” Willett says. “It turned out to be more

nuanced than that.” He had been running a long-term epidemiological study that

followed the diets and heart health of more than 40,000 middle-aged men. Willett found

that if his subjects replaced foods high in saturated fat with carbohydrates, they

experienced no reduction in heart disease. Willett eventually published his research in

the British Medical Journal in 1996.

In part because of Willett’s work, the conversation around fat began to change.

Monounsaturated and polyunsaturated fats–the kind found in some vegetables and

fish–were found to be beneficial to heart health. The Mediterranean diet, rich in fish,

nuts, vegetables and olive oil, surged in popularity. And it’s worth noting that the

Mediterranean diet isn’t low in total fat–not at all. Up to 40% of its calories come from

poly- and monounsaturated fat. Today, medical groups like the Mayo Clinic embrace this diet for patients worried about heart health, and even the fat-phobic AHA has

become receptive to it. “There is growing evidence that the Mediterranean diet is a

pretty healthy way to eat,” says Dr. Rose Marie Robertson, the chief science officer of

the AHA.

But what about saturated fat? Here, the popular wisdom has been harder to change. The

2010 USDA dietary guidelines recommend that Americans get less than 10% of their

daily calories from saturated fat–the equivalent of half a pan-broiled hamburger minus

the cheese, bacon and mayo it’s often dressed with. The AHA is even stricter: Americans

over the age of 2 should limit saturated-fat intake to less than 7% of calories, and the 70

million Americans who would benefit from lowering cholesterol should keep it under 6%

of calories–equal to about two slices of cheddar per day. Some experts say they just

aren’t comfortable letting saturated fat off the hook. “When you replace saturated fats

with polyunsaturated and monounsaturated fats, you lower LDL cholesterol,” says Dr.

Robert Eckel, a past president of the AHA and a co-author of the group’s recent

guidelines. “That’s all I need to know.”

But that’s not the full picture. The more we learn about fat, the more complex its effects

on the body appear.

The Truth About Fat 

The idea that saturated fat is bad for us makes a kind of instinctive sense, and not just

because we use the same phrase to describe both the greasy stuff that gives our steak

flavor and the pounds we carry around our middles. Chemically, they’re not all that

different. The fats that course through our blood and accumulate on our bellies are

called triglycerides, and high levels of triglycerides have been linked to heart disease. It

doesn’t take much of an imaginative leap to assume that eating fats would make us fat,

clog our arteries and give us heart disease. “It sounds like common sense–you are what

you eat,” says Dr. Stephen Phinney, a nutritional biochemist who has studied low-carb

diets for years.

But when scientists crunch the numbers, the connection between saturated fat and

cardiovascular disease becomes more tenuous. A 2010 meta-analysis–basically a study

of other studies–concluded that there was no significant evidence that saturated fat is

associated with an increased risk of cardiovascular disease. Those results were echoed

by another meta-analysis published in March in the Annals of Internal Medicine that

drew on nearly 80 studies involving more than half a million subjects. A team led by Dr.

Rajiv Chowdhury, a cardiovascular epidemiologist at Cambridge University, concluded

that current evidence does not support low consumption of saturated fats or high

consumption of the polyunsaturated fats that are often considered heart healthy.

Though the authors came under criticism for the way they evaluated the evidence, they

stand behind the conclusion, noting that the aim of their study is to show the need for

more research. “The main message is that there’s a lot more work that needs to be done,”

says Chowdhury.

Given that the case on saturated fat was long considered closed, even calls to re-examine

the evidence mark a serious change. But if the new thinking about saturated fats is

surprising, it may be because we’ve misunderstood what meat and dairy do to our

bodies. It’s incontrovertibly true that saturated fat will raise LDL-cholesterol levels, which are associated with higher rates of heart disease. That’s the most damning

biological evidence against saturated fat. But cholesterol is more complicated than that.

Saturated fat also raises levels of the so-called good HDL cholesterol, which removes the

LDL cholesterol that can accumulate on arterial walls. Raising both HDL and LDL makes

saturated fat a cardio wash.

Plus, scientists now know there are two kinds of LDL particles: small, dense ones and

large, fluffy ones. The large ones seem to be mostly harmless–and it’s the levels of those

large particles that fat intake raises. Carb intake, meanwhile, seems to increase the small,

sticky particles that now appear linked to heart disease. “Those observations led me to

wonder how strong the evidence was for the connection between saturated fat and heart

disease,” says Dr. Ronald Krauss, a cardiologist and researcher who has done pioneering

work on LDL. “There’s a risk that people have been steered in the wrong direction by

using LDL cholesterol rather than LDL particles as a risk factor.”

It’s important to understand that there’s no such thing as a placebo in a diet study. When

we reduce levels of one nutrient, we have to replace it with something else, which means

researchers are always studying nutrients in relation to one another. It’s also important

to understand that the new science doesn’t mean people should double down on

cheeseburgers or stir large amounts of butter into their morning coffee, as do some

adherents of ultra-low-carb diets. While saturated fat increasingly seems to have at

worst a neutral effect on obesity and heart disease, other forms of fat may be more

beneficial. There’s evidence that omega-3s, the kind of fat found in flaxseed and salmon,

can protect against heart disease. A 2013 study in the New England Journal of Medicine

found that a diet rich in polyunsaturated and monounsaturated fats significantly

reduced the risk of major cardiovascular events.

And there is variety even within the category of saturated fats. A 2012 study found that

fats in dairy–now the source from which Americans get most of their saturated fat–seem

to be more protective than the fats found in meat. “The main issue here is comparative,”

says Dr. Frank Hu, a nutrition expert at the Harvard School of Public Health. “What are

you comparing saturated fat to?”

The Unintended Diet

The food industry is nothing if not inventive. Faced with a fatwa against fat in the 1980s,

manufacturers adjusted, lining grocery shelves with low-fat cookies, crackers and cakes.

The thinking for consumers was simple: Fat is dangerous, and this product has no fat;

therefore it must be healthy. This was the age of SnackWells, the brand of low-fat

cookies introduced by Nabisco in 1992 that within two years had surpassed the

venerable Ritz cracker to become the No. 1 snack in the nation. But without fat,

something had to be added, and Americans wound up making a dangerous trade. “We

just cut fat and added a whole lot of low-fat junk food that increased caloric intake,” says

Dr. David Katz, the founding director of Yale University’s Prevention Research Center.

“It was a diet of unintended consequences.

Those consequences have been severe. From 1971 to 2000, the percentage of calories

from carbohydrates increased nearly 15%, while the share of calories from fat fell–in

line with expert recommendations. In 1992, the USDA recommended up to 11 servings a

day of grains, compared with just two to three servings of meat, eggs, nuts, beans and fish combined. School districts across the country have banned whole milk, yet

sweetened chocolate milk remains on the menu as long as it’s low-fat.

The idea here was in part to cut calories, but Americans actually ended up eating more:

2,586 calories a day in 2010 compared with 2,109 a day in 1970. Over that same period,

calories from flour and cereals went up 42%, and obesity and Type 2 diabetes became

veritable epidemics. “It’s undeniable we’ve gone down the wrong path,” says Jeff Volek,

a physiologist at the University of Connecticut.

It can be hard to understand why a diet heavy on refined carbs can lead to obesity and

diabetes. It has to do with blood chemistry. Simple carbs like bread and corn may not

look like sugar on your plate, but in your body, that’s what they’re converted to when

digested. “A bagel is no different than a bag of Skittles to your body,” says Dr. Dariush

Mozaffarian, the incoming dean of nutrition science at Tufts University.

Those sugars stimulate the production of insulin, which causes fat cells to go into storage

overdrive, leading to weight gain. Since fewer calories are left to fuel the body, we begin

to feel hungry, and metabolism begins to slow in an effort to save energy. We eat more

and gain more weight, never feeling full. “Hunger is the death knell of a weight-loss

program,” says Duke’s Westman. “A low-fat, low-calorie diet doesn’t work.” Because as

this process repeats, our cells become more resistant to insulin, which causes us to gain

more weight, which only increases insulin resistance in a vicious circle. Obesity, Type 2

diabetes, high triglycerides and low HDL can all follow–and fat intake is barely involved.

All calories, it turns out, are not created equal. “When we focus on fat, carbohydrates

inevitably increase,” says Ludwig, who co-wrote a recent JAMA commentary on the

subject. “You wouldn’t give lactose to people who are lactose intolerant, yet we give

carbs to people who are carb intolerant.”

Ultra-low-carb diets have come in and out of vogue since Dr. Robert Atkins first began

promoting his version nearly 50 years ago. (It has never been popular with mainstream

medicine; the American Diabetic Association once referred to the Atkins diet as a

“nutritionist’s nightmare.”) Studies by Westman found that replacing carbohydrates

with fat could help manage and even reverse diabetes. A 2008 study in the New England

Journal of Medicine that looked at more than 300 subjects who tried either a low-fat, a

low-carb or a Mediterranean-style diet found that people on the low-fat diet lost less

weight than those on the low-carb or Mediterranean diet, both of which feature high

amounts of fat. Those results aren’t surprising–study after study has found that it’s very

difficult to lose weight on a very low-fat diet, possibly because fat and meat can produce

a sense of satiety that’s harder to achieve with carbs, making it easier to simply stop

eating.

Not every expert agrees. Dr. Dean Ornish, founder of the nonprofit Preventive Medicine

Research Institute, whose low-fat, almost vegan diet has been shown in one study to

reverse arterial blockage, worries that an increase in animal-protein consumption can

come with health problems of its own, pointing to studies that link red meat in particular

to higher rates of colon cancer. There’s also the uncomfortable fact that meat, especially

beef, has an outsize impact on the planet. Nearly a third of the earth’s total ice-free

surface is used in one way or another to raise livestock. Even if eating more fat is better

for us–which Ornish doesn’t believe–it could carry serious environmental consequences

if it leads to a major increase in meat consumption. “These studies just tell people what

they want to hear,” says Ornish. “There’s a reductionist tendency to look for the one magic bullet.”

The war over fat is far from over. Consumer habits are deeply formed, and entire

industries are based on demonizing fat. TV teems with reality shows about losing weight.

The aisles are still filled with low-fat snacks. Most of us still feel a twinge of shame when

we gobble down a steak. And publishing scientific research that contradicts or questions

what we have long been told about saturated fat can be as difficult now as it was for

Willett in the ’90s. Even experts like Harvard’s Hu, who says people shouldn’t be

concerned about total fat, draw the line at fully exonerating saturated fat. “I do worry

that if people get the message that saturated fat is fine, they’ll [adopt] unhealthy habits,”

he says. “We should be focusing on the quality of food, of real food.”

Nearly every expert agrees we’d be healthier if more of our diet were made up of what

the writer Michael Pollan bluntly calls “real food.” The staggering rise in obesity over

the past few decades doesn’t just stem from refined carbohydrates messing with our

metabolism. More and more of what we eat comes to us custom-designed by the food

industry to make us want more. There’s evidence that processing itself raises the danger

posed by food. Studies suggest that processed meat may increase the risk of heart

disease in a way that unprocessed meat does not.

How we eat–whether we cook it ourselves or grab fast-food takeout–matters as much as

what we eat. So don’t feel bad about the cream in your coffee or the yolks in your eggs or

the occasional steak with béarnaise if you’ve got the culinary chops–but don’t think that

the end of the war on fat means all the Extra Value Meals you can eat. As Katz puts it,

“the cold hard truth is that the only way to eat well is to eat well.” Which, I’m thankful to

note, doesn’t have to include skim milk.

This appears in the June 23, 2014 issue of

TIME.