February 7, 2006

A low fat diet -- for women, at least -- shows no health benefit.

Just as I suspected.

UPDATE: The NYT front-pages its story on the study:
"These studies are revolutionary," said Dr. Jules Hirsch, physician in chief emeritus at Rockefeller University in New York City, who has spent a lifetime studying the effects of diets on weight and health. "They should put a stop to this era of thinking that we have all the information we need to change the whole national diet and make everybody healthy."

The study, published in today's issue of The Journal of the American Medical Association, was not just an ordinary study, said Dr. Michael Thun, who directs epidemiological research for the American Cancer Society. It was so large and so expensive, Dr. Thun said, that it was "the Rolls-Royce of studies." As such, he added, it is likely to be the final word.

Of course, you can also get experts to reflexively insist that we still need to cut fat from our diet! And look at the comments to this post: they do the same. Don't dare take this comprehensive study to mean you can ignore the nanny scientists who would like to hover over your every meal.

34 comments:

AJD said...

Well, that's not exactly what the story says:

"Several experts cautioned, however, that the study hints that there still may be some benefits to reducing the total amount of fat in the diet, especially for breast cancer. In addition, there is clear evidence from this and other studies that particular fats -- saturated fats from meat and trans fats from processed foods -- are unhealthful and should be avoided."

Aspasia M. said...

What cc said.

Some fats are good and others are bad for the heart.
We need the good fat. (Omega 3, I think?) We need to get rid of the bad fat.

Good fats: fish (salmon), olive oil, fats in nuts, ect.

Bat fats: lard, saturated fat, ect.

Christopher Althouse said...

What about us men? Do we not matter?

XWL said...

So does that mean it's OK to eat Mohammedan pastries again?

(or if you prefer the infidel name, Danishes)

And Mr. Cohen, of course men don't matter, didn't you pay attention in college?

Maxine Weiss said...

"....there is clear evidence from this and other studies that particular fats -- saturated fats from meat and trans fats from processed foods -- are unhealthful and should be avoided."

Peace, Maxine

Bruce Hayden said...

I think that there is good reason to believe that males and females might have different needs as to fat and other nutrients. Females, for example, when healthy, tend to carry more body fat - presumably to support pregnancy.

Bruce Hayden said...

Let me add that one of the most extreme examples of different body fat levels between men and women that I have ever seen is in the Inuit. For the most part, the men are thin, and the women quite rotund. The explanation is, IMHO, that the men need to burn a lot of fat to go out on the ice every day, whereas the women stay indoors, and on a similar diet, tend to get quite fat. This is quite noticable if you ever to to our northernmost settlement, Barrow.

Ann Althouse said...

Chris: Most studies are done on men and then the assumption is that it applies to women too. It's harder to do studies on women because they don't want to deal with pregnancy and possible pregnancy, so it was important to do this.

Fat really is different for women, as Bruce indicates. Our natural bodies really are more proportionally fat. Breasts are mostly fat. And women who get too thin lose thei menstrual periods. We have a special relationship to fat.

And look at all of you people desperately seeking a way to boss women around about what to eat despite this study. There is NOTHING incorrect in my post, which refers to a LOW FAT DIET.

Geoduck: I assure you I'm avoiding "bat fat." Yuck!

AJD said...

The "desperation" in this post is not in the comments, Ann. Or should I use screaming caps for "not."

Pogo said...

Speaking of the nanny approach to monitoring everyone's diet, consider the 12/04 article in BMJ discussing the "Polymeal, a more natural, safer, and probably tastier (than the Polypill) strategy to reduce cardiovascular disease by more than 75%."

They are describing, in effect, the "perfect" food for humans that should be eaten every day, for every meal. People Chow.

Unfortunately for "Concerned Citizen," Ann is on target here. A low fat diet did not have the health benefits attributed to it, yet the nannies insit we eat it anyway. That's no longer science, but dogma.

AJD said...

What?! I'm not insisting that anyone eat anything. I just insist that if you "summarize" an article that you do not leave about the portions that contradict your claim. Apparently that insistence is enough to bring down the Wrath of Ann. I wonder why. Protesth too much comes to mind.

Pogo said...

Concerned Citizen,

How does your statement, The "desperation" in this post is not in the comments, Ann. Or should I use screaming caps for "not."

translate into
I just insist that if you "summarize" an article that you do not leave about the portions that contradict your claim.??

Are those two sentences even remotely related?

Ann's summary is correct. While "experts" may caution "that the study hints that there still may be some benefits to reducing the total amount of fat in the diet", hints are not science. It's junk, debris, detritus; not a basis for scientific conclusion.

What the data permit them to state is that their hypothesis was unproven, and diet made no difference. Nothing more. Reading "hints" into that is either self-deceiving or fraudulent. I suspect both.

Meade said...

You gonna eat that last piece of bacon?

tcd said...

As Homer Simpson would say, "Bacon up that sausage, boy!"

Calico Cat said...

Low fat diet: lie.
Low cholesterol diet: lie.
Need to lose weight: lie.
Take vitamins: lie.

Joan said...

Thanks for this post, Ann.

I'm so tired of defending saturated fats (from meat) against the slander that they are just as bad for you as trans fats ("fake" fats, aka hydrogenated or partially hydrogenated oils.) The studies that implicated saturated fats were poorly designed and mixed trans fats and saturated fats together, and then drew the same conclusion about them both, even though there is no mechanism for showing how saturated fats are harmful.

Consider: heart disease was very rare in this country up until the widespread use of vegetable oils and hydrogenated oils. If saturated fats are so bad for us, why wasn't heart disease rampant when that's all that people ever ate? (I won't even get into the horrors inflicted on our metabolisms by high fructose corn syrup.)

Yes, I'm going to eat that last piece of bacon. Pass the butter! (No, I don't butter my bacon.)

Best strategy? Read the ingredient lists of the foods you eat. If it was made in a lab somewhere, don't eat it. Eat real food and you'll be OK.

LetMeSpellItOutForYou said...

Joan said: heart disease was very rare in this country up until the widespread use of vegetable oils and hydrogenated oils. Really? Never heard that. Who said so? Could it be one of those cases, as in cancer, where increased incidence is due to longer lifespans?

Jeremy said...

The article starts, "Low-fat diets do not protect women against heart attacks, strokes, breast cancer or colon cancer..." But doesn't seem to answer the most important question: Do low-fat diets protect against getting fat? Isn't that the question that folks are really after? I think it's safe to say that more women are concerned with looking fat than the "side effects" of poor health. Am I out to lunch here?

37921 said...

Joan, you say "heart disease was very rare in this country up until the widespread use of vegetable oils and hydrogenated oils."

Do you think smoking might have had a bit to do with that?

37921 said...

Actually, the introduction of hydrogenated oils coincided with a major decline in deaths from cardiovascular disease. However, according to the CDC the main reason is the reduction in cigarette smoking.

Ann Althouse said...

Jeremy: It seems that people started getting really fat after they tried to follow the low fat advice.

Pastor_Jeff said...

I'm usually a cereal person, but this morning I had a toasted, buttered bagel with sausage patty for breakfast, along with a slice of homemade coconut pound cake (don't ask how many eggs and how much butter) and coffee. Mmmmmm.

According to the Althouse Rule on Gender Difference Reporting, what we now need is another study showing that men do need a low-fat diet - once again demonstrating that women are superior.

k said...

GAAAAHHH! Moderation. That's all it's ever been and all it will ever be. Nothing is inherently "good" or "bad." (In some sense, even a poison can be consumed in small enough quantites as to be innocuous. Apple seeds contain cyanide, e.g.) Balance is key and moderation the solution. And as soon as everyone quits worrying about his (and MY) choice of foods, we'll all be happier.

Meade said...

Joan, let me get this straight: You hogged all the bacon AND now you want me to get up and pass you the butter?

Sheesh! Can't you reach?

Tibore said...

..."The eight-year study of nearly 50,000 middle-age and elderly women..."

On the one hand, the sample size was very large, which is always good. On the other, two points:

1. "Middle-aged and elderly"... perhaps the "damage" was done by that point, damage being that activity/habit/diet/lifestyle which predisposes a person towards the diseases mentioned. Would a similarly large study following children into adulthood have the same result? Obviously, it's impossible to tell without conducting such a study, but my point is that the sample groups age and previous history probably has some bearing. All this study is saying is that the risk isn't reduced for middle aged and elderly women. Extrapolating to humans outside that group is a little precarious.

2. This is still only a correlative study. What other factors come into play? How many of those subjects had a family history of the diseases who's risk was being studied? That, if I remember correctly, was a very big factor in predisposition to heart disease, cancer, etc., and perhaps big enough to offset whatever benefits came from other sources, such as lowered fat diets.

"...In addition, there is clear evidence from this and other studies that particular fats -- saturated fats from meat and trans fats from processed foods -- are unhealthful and should be avoided..."

The main thrust of this study doesn't undo or contradict any other ones. Rather, it expands the overall knowledge. The study is saying that simply parroting the message "low fat good" is too simplistic. What types of fat are being taken in? Also, what are the lifestyles in question? All other things being equal (height, weight, frame, etc.), a person who excercises regularly can take in more fat.

On top of that, let's not misread this story and think that there were zero benefits to reducing fat:

"Researchers said they did see benefits from the low-fat diet. Women with the highest intake of fats at the beginning of the study had a statistically significant reduction in the risk of heart disease and breast cancer. And those who reduced fat intake had a lower incident of polyps, considered to be a precursor of colorectal cancer."
http://www.chron.com/disp/story.mpl/front/3643678.html

And also, here's a point from an epidemiologist:

"And Dr. Michele Forman, an epidemiologist, suggested the study's publication was premature, just before women in it hit the peak years for colorectal cancer — their late 60s and early 70s. (The average age women were when the study began was 62.)"

And last, this "final word" isn't really the final word:

"Study investigators said they plan to follow participants for another eight years."

Source: Same www.chron.com link as above)

Let's see how the participants fare then.

All in all, here's one lesson one doctor says can really be taken from the study:

"Gould said if there was a lesson from the study it was that people have to be serious about reducing fat, not take a casual approach to it."

(Source: Again, same www.chron.com link as above).

PatCA said...

I've followed the low fat dogma forever and had breast cancer (now fine) and gained a pound or two every year. I saw my future and went on the South Beach after a 40-ish friend lost fat and inches quickly. I thought it was a scam until I read the doctor's analysis, and it corresponds exactly with this study. He stresses good fats, not trans fats, and good carbs. I lost pounds and inches right away. I'll be interested to see if my cholesterol goes down...

Sedentary people simply do not need 4 servings of carbs, especially processed carbs, per day.

No, I am not being paid for this testimonial, LOL!

Aspasia M. said...

Well, lately I've been eating McDonalds, so I can't begin a career as a food nanny anytime soon. I love my cheeseburgers.

Here's the deal. The study is confusing when it comes to cholesterol. It's not just a question of "good" or "bad" cholesterol, it's what kind and how much, and what size are your LDLs and HDLs.

(And inherited disorders are critical when you are evaluating whether you are at risk for heart attack or stroke.)

Here's my simplistic summary: We need the good kinds of cholesterol that are increased by eating things with good fat and through exercise. And, the same diet is not right for everyone.

A sophisticated blood analysis is done by by Berkely Heartlab. The analysis not only looks at LDL and HDL, but it also looks at the size of the cholesterol.

Ann Althouse said...

Geoduck: I just don't believe that avoiding eating cholesterol is what helps with cholesteral problems, but I'm only talking about myself. I eat all the butter and red meat I want and my HDLs are especially good and my LDLs really low. I'm not going to change anything. If I had a problem, I'd probably be more antsy about the who thing.

somross said...

I immediately celebrated on hearing the news by having a chocolate ice cream soda with two cherries.

Maxine Weiss said...

Ann: Be careful. You don't have a problem with cholesterol now, but none of knows what's in the future.

High cholesterol is bad, period. It takes a number of years to build up. It may look like you don't have a care in the world, right now, but that doesn't mean there isn't something stirring and building, and waiting to explode 20 years from now, 10 years from now, while you were indulging.

(Why do I sound like your Grandmother?)

This study is flawed, precisely because it didn't take into account cholesterol. The research subjects could have feasibly stuffed themselves with a lot of non-fat dairy products----all non-fat---but still loaded with cholesterol.

Just cutting out fat is meaningless. It's the excess cholesterol which your body doesn't need. Your body (Am I preaching?) makes all the cholesterol, in the liver, that it will ever need.

If you never eat anything animal, or anything animal products----you don't take in excess cholesterol.

Yes, a totally vegetarian diet. Vegans. Nobody wants to hear that. But, a vegetarian diet works. That wasn't the diet the research subjects were put on. For all we know they pigged out on non-fat diary products, poultry and fish.....stuff that's traditionally low in fat---yes, however, still high in cholesterol.

Fat, alone, doesn't tell the whole story. It's the cholesterol coming from animal products in an animal diet.....which is going to contribute, not only to heart disease, but blood pressure and stroke!

End of lecture. Grandma's tired!

Peace, Maxine

Aspasia M. said...

I want another cheesburger. And I want somross's shake.

Dinner tonight is mostly black beans and rice with a little steak in a tortilla. And spinach and fruit. I'm selling it as "brain food" to my husband.

dearieme said...

Nice to see some backing for that big Norwegian study of some years ago: "These studies are revolutionary" now seems to mean a replication?

Maxine Weiss said...

Chocolate's a vegetable, I tell you. It comes from the ground---the cocoa bean.

Some chocolate and a glass of red wine----all vegetarian!

Peace, Maxine

Joan said...

Maxine: that's my kind of diet.

Very few people are affected by the cholesterol they consume. High cholesterol is a symptom of heart disease and artheriosclerosis, not the cause.

Eggs are good for you: eat up!

I first read about the incidence of heart disease being linked to fake fats in an online nurse's continuing education course, which is no longer available. I did some searches and couldn't find a chart of the incidence of CVD, as opposed to the morbidity; it's an important distinction in this discussion. Here's an Australian site which has some pertinent discussion.