“Time to Retire the Low-Carb Diet Fad” writes Ellen Ruppel Shell at The Atlantic. The headline is accompanied by this photo:
The implicit message is: carbs=good, fat=bad. Remember the USDA’s food pyramid and recommendation of a diet consisting mostly of carbohydrates? Same old message. The “conventional wisdom” wins the day.
Never mind the science that says that saturated fats are actually good for you and are not the cause of heart disease, and that the obesity epidemic is not caused by eating saturated fats, but carbohydrates, particularly in the form of sugars, like high-fructose corn syrup, and that carbohydrates just turn into sugar (glucose) in your body and affect your insulin levels, which in turn effects how your body stores energy as fat.
Shell begins her argument with this:
“Steak, cream pies, hot fudge — those were thought to be unhealthy — precisely the opposite of what we now know to be true.” –Doctors in the year 2173 in Woody Allen’s Sleeper
A version of Woody Allen’s fantasy has in recent years been making the talk show circuit. Marbled steaks, bacon, greasy burgers dripping with cheese, we’re told, are not to blame for obesity and cardiovascular disease. Nope, it’s bananas, whole wheat toast, acorn squash, peas, pasta, rice and boiled potatoes that’s making us fat and sick. So feel free to double up on those pork chops and sausage patties!
Notice Shell does not cite any real advocate of a low-carb diet, but a comedy film. Notice how this sets up a strawman argument for her to knock down. Oh my gosh, people are arguing on the “talk show circuit” that eating cream pies, hot fudge, and greasy burgers are just fine for you! Well, who has ever made such an argument in real life (as opposed to in a fantasy movie)?
I don’t know who Shell thinks she is referring to, apart from Woody Allen, but two guys I get health information from are Dr. Mercola and Mark Sisson, both of whom advocate cutting back on carbs and replacing them with saturated fats alongside lots of vegetables, fruit, nuts, etc., and neither of whom would ever argue such ridiculous nonsense as Shell sets up to knock down here.
Unfortunately, today’s long anticipated announcement of the results of a 25-year Swedish study pours rain on the porky parade. What apparently makes this report particularly potent is that it is the first nationally and regionally conducted long-term epidemiological study of low carbohydrate diets. And the results were categorical.
The study concludes that, over time, reducing animal fat intake decreased blood cholesterol levels, and that a high fat low carbohydrate diet increased blood cholesterol levels. On average, Swedes who switched from a lower fat diet to a higher fat/lower carbohydrate diet saw their blood cholesterol creep up — despite an increased use of cholesterol lowering medication.
She characterized anyone who might happen to disagree with her thusly:
Low carbohydrate evangelists will almost certainly attack today’s announcement—and perhaps this post—with biblical fury. They’ll make their usual claim: that this is yet another conspiracy of scientists who just don’t get it, scientists who don’t understand nutrition, scientists who somehow made it through their PhD’s and MD’s without knowing the first thing about how the human body works.
Do scientists know everything there is to know about how the human body works? Is there no further knowledge to be gained? Is there no possibility of evolving thought in nutrition, because we already know everything? Isn’t it possible that scientists don’t know everything, that there is more to learn, and that the science behind our understanding of nutrition can change? Is it really reasonable to characterize people who disagree with Shell’s message as though they were cultist conspiracy theorists who reject enlightenment and remain trapped in a bygone era of ignorance?
Here’s what the study actually has to say about that:
The association between nutrition and health is complex…. [T]he data are conflicting or insufficient to convict or free total fat intake or other fat fractions with respect to CVD [cardiovascular disease] risk. Thus further research is needed, especially focusing on long-term dietary intake.
Oh! So it seems questioning “conventional wisdom” may not be such a cultish, ignorant thing to do after all. Shell makes no mention of this “conflicting data” and need for “further research” when touting this study as proving her case and putting to rest any doubts or arguments to the contrary.
Shell quotes the study’s head researcher, Ingegerd Johansson, saying:
The association between nutrition and health is complex. It involves specific food components, interactions among those food components, and interactions with genetic factors and individual needs. While low carbohydrate/high fat diets may help short term weight loss, these results of this Swedish study demonstrate that long term weight loss is not maintained and that this diet increases blood cholesterol which has a major impact on risk of cardiovascular disease.
Ah, some more conventional wisdom. Here is what Dr. Ron Rosedale has to say about that (emphasis added):
Cholesterol is not the major culprit in heart disease or any disease…. The fixation on cholesterol as a major cause of heart disease defies the last 15 years of science and deflects from real causes such as the damage (via glycation) that sugars such as glucose and fructose inflict on tissues, including the lining of arteries, causing chronic inflammation and resultant plaque.
Furthermore, look at what was included in the “fats” category for the purposes of this study Shell cites to prove her case:
Fats used for spreading on bread and cooking, dairy products, oil for salad dressing or cooking, various types of meats and sausages as main dish or on sandwiches, pizza, deep- fried potato chips (French fries), and non-sweet snacks (including potato and maize crisps (chips), cheese-flavoured puffed products, popcorn, and peanuts) were identified to be associated with high fat intake….
We come back to Shell’s strawman argument. What real advocate of a lower-carb, higher-saturated fat diet would encourage eating pizza, potato chips, and popcorn as part of a healthy diet? Notice that we are not talking strictly about saturated fats here, and that some of these foods are not only high-fat but also high carbohydrate (e.g., pizza).
Additionally, while Shell touted this study as finally putting to rest this “fad” of a higher-saturated fat and lower-carb diet, how “the results were categorical” “that a high fat low carbohydrate diet increased blood cholesterol levels”, here’s what the study actually says about that (emphasis added):
Our study design does not allow a causal evaluation of the relationship between the increased fat intake … and the increased cholesterol levels …, although the parallel trends would suggest such a relationship.
Well, now, that’s not so “categorical”, is it? I know, I know, I must be an evangelical conspiracy nut to point out Shell’s errors and what appears to me to be either lazy reporting or outright dishonesty. I presume the former, but here’s more evidence of the latter. The study states:
There is strong support for protective effects of dietary foods/factors in relation to cholesterol levels and coronary heart disease; such positive foods are fish, vegetables, nuts and the “Mediterranean diet”. Harmful dietary factors include trans fatty acids, foods with high glycaemic index, and “Western diet” patterns.
Gosh, doesn’t that sound very similar to what advocates of a lower-carb, higher-saturated fat diet have been saying? The Mediterranean diet, by the way, is “rich in fruits, vegetables, fish and healthy fats such as olive oil”, as Dr. Mercola explains (emphasis added). Dr. Mercola talks about how this diet could lower risk for heart disease in another article, where he also says to:
Eliminate Grains and Sugars: You need to eliminate foods that your body will react to by creating insulin, which includes all types of sugars (especially fructose) and grains—even “healthy” grains such as whole, organic grains. Reducing or eliminating carbohydrates is one of the most potent longevity strategies out there, for the very reason that you’re improving your insulin sensitivity. This means avoiding all breads, pasta, cereals, rice, potatoes, and corn (which is in fact a grain). You may even need to avoid fruits until your blood sugar is under control.
Now, Shell would disparage this recommendation of cutting down on carbohydrates, but I see nothing in the study she cites to bolster her case that actually contradicts Dr. Mercola’s advice.
And remember what Shell quoted Johansson as saying? Once more:
While low carbohydrate/high fat diets may help short term weight loss, these results of this Swedish study demonstrate that long term weight loss is not maintained….
When I read that I naturally concluded that he meant his study showed that people who were on such a diet regained the weight they had lost in the short term over the long term, and perhaps then some. But that’s not what the study says at all. Rather, it states (emphasis added):
Notably, the increased fat intake was not associated with any reduction or stagnation of the increasing levels of BMI in the northern Sweden population, even though several studies indicate positive effects of LCHF [low-carb, high-fat], i.e. weight loss in a short-term perspective. However, evidence for weight loss effects beyond six months is lacking, and long-term safety is controversial, i.e. some studies report adverse health effects and others do not.
It seems Johansson should have chosen his words more carefully, and Shell should have clarified what he meant for readers so as not be misled, as I was when reading that quote from him.
The study concludes:
In conclusion, men and women in northern Sweden decreased their reported intake of total and saturated fat in the first years following the introduction of an intervention programme, but after 2004 fat intake increased, especially saturated fat and butter-based spread for bread and butter for cooking. Supportive opinions in media for high-fat diets seem to have had an impact on consumer behaviour. Initially beneficial and thereafter deleterious changes in blood cholesterol paralleled these trends in food selection, whereas a claimed weight reduction by high-fat diets was not seen in the most recent years.
Once again, it is important to emphasize that this study was not really designed to examine the effects of the kind of dietary recommendation of higher saturated fats and lower carbs that Shell is disparaging, as the example of eating buttered bread (i.e., carbohydrates) illustrates. Advocates of the kind of diet Shell says you shouldn’t eat that I know, like Dr. Mercola and Mark Sisson (and leaving Woody Allen out of it), would tell you that the butter is fine, but leave out the bread. They would not tell you that pizza, potato chips, and popcorn are examples of healthy fats that are okay to eat under this diet.
In fact, I find this study to be pretty much irrelevant to the conclusion Shell draws by means of misinforming her readers about what the study actually says.
No one suggests that eating large amounts of isolated simple carbohydrates (aka simple sugar) is good for anyone; it’s not. Soda pop should not play a starring role in America’s diet, and sweeteners of all kinds should be consumed in moderation — which is to say, most of us should eat less of them. But the popular folk lore that carbohydrates found naturally in fruits, vegetables and grains are responsible for the nation’s epidemic of obesity and its co-morbidities of heart disease and diabetes is about as realistic as a Woody Allen fantasy.
Wow, nice strawman argument. I would love to know who has ever argued “that carbohydrates found naturally in fruits, vegetables and grains are responsible for the nation’s epidemic of obesity”—besides some character in some fantasy film.
Why am I writing this? I’m not a scientist, and I’m not one of those health gurus. But I can tell you this: I have benefited enormously from reducing my carbohydrates intake, including eliminating grains, and replacing it with more saturated fats, vegetables, fruit, and nuts. I would propose this to anyone who would like to put Shell’s argument to the test: try Mark Sisson’s 21-Day Total Body Transformation and, at the end of those 21 days, ask yourself whether you don’t look and feel much better.
I know I do. Forget the scientists. Do your own experiment. Listen to your own body. Let it tell you who is right and who is wrong.