In the article "The Overflowing American Dinner Plate", Bill Marsh cites USDA data showing a 59% increase in fat consumption from 1970 to 2006, coinciding with the doubling of the obesity rate in America. However, according to Centers for Disease Control NHANES nutrition survey data, total fat intake in the US has remained relatively constant since 1971, and has actually decreased as a percentage of calories. The apparent discrepancy disappears when we understand that the USDA data Marsh cites are not comprehensive. They do not include the fat contained in milk and meat, which have been steadily decreasing since 1970.
The change Marsh reported refers primarily to the increasing use of industrially processed vegetable oils such as soybean oil. These have gradually replaced animal fats in our diet over the last 30 years. Since overall fat intake has changed little since the 1970s, it cannot be blamed for rising obesity.
Monday, August 11, 2008
Letter to the Editor
I wrote a letter to the New York Times about their recent article "The Overflowing American Dinnerplate", which I reviewed here. The letter didn't get accepted, so I will publish it here:
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11 comments:
Hi Stephan,
Really appreciate your trawling through the data on food consumption like this. Interesting posts. Also interesting to see how the press view exactly the same data...
Thanks
Peter
Hi Chainey,
When you send your letter to them by e-mail, they send you back an automated reply that says something like "if you haven't heard from us in 5 days, you can assume it wasn't published". Fortunately, their content is all online so I don't have to buy it! Actually, I do get the NYT but only 3 days a week.
I sent the letter to my Mom so she could take a look at it. She's been doing this sort of thing for a long time. She told me they probably wouldn't publish it because it makes them look like amateurs. She said they love publishing differences of opinion and that sort of thing, but not letters that fundamentally undermine their articles. She also mentioned, like you said, that they'll often eviscerate letters to the editor, removing the key points in the name of space.
Well I'm new to the newspaper game, so I'm expecting a few knocks. Hopefully I'll get through eventually.
Hi Peter,
Glad it's helpful. This whole experience has not increased my faith in the media.
I don't think your letter makes them look like amateurs; I think they do a perfectly good job of looking like amateurs on their own.
Debs
Food Is Love
Stephan, I think you'll find resistance from the mainstream media to anything that questions or refutes the prevailing "wisdom" about fats. It won't be limited to the NYT (or fats, for that matter). Think about how much mis- or disinformation you read in the press everyday. Think about the entrenched interests it represents. Smart people increasingly look to the web to get beyond the propaganda that passes for factual reporting in the media.
That's why what you are doing here at your blog is important and good work. Improving world health one reader at a time.
Thanks Yuneek. I think you're right about encountering resistance. I've been trying to submit an op-ed lately. It's been rejected by the NYT and LAT so far. I won't try to blame that on anti-fat bias (rather than the quality of my own piece).
However, I will note that 3 weeks after I submitted my piece to the NYT, they published the article I dismantled 3 posts ago. That article used the same references, some of the same data, and the same general idea as my submission (comparing US diet trends to obesity rates). Except they suggested that fat is the problem due to a misinterpretation of the USDA data. In my article, fat was exonerated. I have a hard time believing it's a coincidence.
Hi Stephan:
I think you did a better job taking apart the USDA data than Taubes did in his book. Gary didn't put nearly enough blame on the replacement of saturated fats with toxic vegetable oils. He only had a few words here and there about it. I suspect that his editors made him tone it down. Sally Fallon said publishers won't accept diet or cookbooks unless you mention canola oil favorably. Even Atkins gave soybean oil, corn oil, mayonnaise, and salad dressing the thumbs up. I would not touch those foods if I was starving. I wouldn't care if they were cold-pressed and unrefined. They are inherently bad.
Bruce,
Gary doesn't seem to be taken by the vegetable oil story, judging by the e-mails we've exchanged. He points out that wheat flour and sugar are sufficient to cause 'physical degeneration' in the absence of vegetable oil. He's correct about that, although I still believe modern vegetable oils cause their own problems and exacerbate the 'degeneration'.
He's really focused on one issue: carbohydrate. I do think the story is more complex than how he portrays it (i.e. white flour is worse than root veg given equal carb content), but I also think he's bravely posing an interesting and testable hypothesis and exposing a lot of hypocrisy.
I'm content seeing him fry one fish at a time.
Gary notes in his book that all the studies blaming fat for cancer used high-PUFA oils. Of course sugar and flour are enough to cause "physical degeneration" by themselves, but it seems to me that high-PUFA oils act as a catalyst and vastly accelerate this degeneration. No healthy tribe ate an abundance of PUFAs. Even the Eskimos ate 10% or less based on my reading. And they had some problems with bleeding and bruising, because of that high intake of omega-3.
Gary doesn't accept that trans fats are bad, either. He's on the fence. In fairness, the evidence is flawed or largely epidemiological. But you do have animal studies showing that hydrogenated oils cause beer belly. And I've heard anecdotal reports of the same thing. At the least, there is no healthy group that ate Crisco or soybean oil and no evidence that such oils will enhance health, even in the absence of carbs.
Gary also ignores the existence of healthy cultures eating a high-carb diet, which I'm glad you and Peter are willing to point out. Some say that Americans used to eat 500g of carbs a day in 1909. They also ate 3500 kcal a day. But few people in those days were obese. Gary's right that they ate less sugar and flour, but they also didn't have vegetable oils, except coconut, olive, and a few other natural ones.
Bruce,
I'm interested in the reading you've done on the PUFA content of the Inuit diet. Totally carnivorous Inuit must have eaten 65-75% of energy as fat, so to get 10% n-3 they would have to eat from sources that averaged 15% or so. I just looked up seal oil and it looks like it's between 15 and 30 percent n-3, about 1% n-6. Fish would be more unsaturated.
How do you think they managed to keep PUFA around 10% of energy? I did notice that whale is lower in PUFA, and I know ungulates don't have much. Did they seek out fats that are lower in PUFA?
The Eskimos ate a lot of caribou, I think. They also ate birds which do not have as much PUFAs as fish. The amount of PUFAs in wild seafood are lower than modern farmed varieties. Whale is probably lower than others since it's a mammal. Most fish have very low fat content. Wild salmon's like 6% fat, while whole chicken is 15% fat. Wild salmon only has about 2.5% PUFAs by weight. They would've had to eat 1 kg of salmon to get 25 g of PUFAs. The 10% figure was from the Nutri-Spec newsletter. WAPF has given a target of 4% PUFAs based on most of the tribes Price studied. I think their low-carb diet protected them to some extent, plus living in a pristine area. Nowadays the world is fill of pollution and chemicals. Saturated fats are known to protect against toxins, while PUFAs make it worse. See Ray Peat's article "Fats and Degeneration", for ex.
http://raypeat.com/articles/articles/fats-degeneration.shtml
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