It was a brutal weekend. I spent nearly all of it, including last night, extracting extremely inconsistent data from Excel spreadsheets into a database for a customer. Yuck.
After that headache, I thought I’d go ahead and give myself a migraine by reading another major section of the 2010 Dietary Guidelines. This one was titled Carbohydrates. It was pretty much a love letter … if anyone dared write a love letter in Engfish. (Dear One – it has been determined by moderately strong evidence that I typically experience an increase in levels of mood-elevating hormonal secretions when you are in close proximity, as measured by the vertical distance between subject one (you) and subject two (me), thus indicating …)
Before we get into the details, here’s the summary:
- Carbohydrates don’t make us fat
- Carbohydrates don’t cause heart disease
- Carbohydrates don’t cause type 2 diabetes
- Carbohydrates don’t cause anything bad, except maybe cavities
- Carbohydrates from whole grains will cure all your ailments
- Shut up and eat your carbohydrates
Stunning revelations from a committee empanelled by a government that’s heavily into the grain business. Here’s some of the opening Engfish:
The role of carbohydrates in the diet has been the source of much public and scientific interest. These include the relationship of carbohydrates with health outcomes, including coronary heart disease (CHD), type 2 diabetes (T2D), body weight, and dental caries. The 2010 DGAC conducted NEL evidence reviews on these and other carbohydrate-related topics. The Committee also relied on evidence contained in the 2002 Dietary Reference Intakes (DRIs) report and conducted a non-NEL review of recent literature to specifically examine the relationship of carbohydrates with CHD, T2D, behavior, and cognitive performance. No detrimental effects of carbohydrates as a source of calories on these or other health outcomes were reported.
Well, that’s it, then. The committee promised they’d review all the relevant scientific literature, and now they’re telling us carbohydrates have no detrimental effects. I can quit reading the report and spend the rest of tonight watching re-runs of Seinfeld.
Dangit, no I can’t. Thanks in part to my high-fat diet, I have an excellent memory. And I seem to recall some important studies (many of which I read, even if the committee didn’t) found a link between high-glycemic carbohydrates and disease. There was even an editorial about the subject in a recent edition of the American Journal of Clinical Nutrition. Here are some excerpts (IHD means ischemic heart disease, in case you didn’t know):
Numerous epidemiologic studies have found that higher intake of refined carbohydrates (reflected by increased dietary GL) is associated with greater risk of type 2 diabetes and IHD, whereas higher consumption of whole grains protects against these conditions.
In this issue of the Journal, Jakobsen et al compared the association between saturated fats and carbohydrates with IHD risk among 53,644 men and women in a Danish cohort of the Diet, Cancer, and Health Study. During 12 y of follow-up, 1943 incident cases of myocardial infarction (MI) were diagnosed. Multivariate analyses showed that saturated fat intake was not associated with risk of MI compared with carbohydrate consumption- a finding consistent with the results from a recent pooled analysis and a meta-analysis. However, replacement of saturated fat with high-GI-value carbohydrates significantly increased the risk of MI (relative risk per 5% increment of energy from carbohydrates).
This study is notable for its large size, long duration of followup, and detailed assessment of dietary and lifestyle factors. It is the first epidemiologic study to specifically examine the effects of replacing saturated fats with either high- or low-quality carbohydrates, and it provides direct evidence that substituting high-GIvalue carbohydrates for saturated fat actually increases IHD risk.
Replace saturated fat with high-glycemic carbohydrates, and the risk of heart disease goes up. Perhaps the committee will at least acknowledge that we should be avoiding high-glycemic, refined carbohydrates. Let’s see what they have to say on the matter:
When selecting carbohydrate foods, there is no need for concern with their glycemic index or glycemic load. What is important to heed is their calories, caloric density, and fiber content.
Got that? High glycemic, low glycemic … nothing to worry about. Here’s the committee’s fuller conclusion:
Strong and consistent evidence shows that glycemic index and/or glycemic load are not associated with body weight and do not lead to greater weight loss or better weight maintenance. Abundant, strong epidemiological evidence demonstrates that there is no association between glycemic index or load and cancer. A moderate body of inconsistent evidence supports a relationship between high glycemic index and type 2 diabetes. Strong, convincing evidence shows little association between glycemic load and type 2 diabetes. Due to limited evidence, no conclusion can be drawn to assess the relationship between either glycemic index or load and cardiovascular disease.
So the only link negative link to high-glycemic foods is with type 2 diabetes, and by gosh, the evidence is inconsistent on that one. After several pages of research summaries and citations (which I suspect were cherry-picked), the committee declares the evidence “mixed” and tells us the glycemic index or load doesn’t make a difference.
I found that fascinating because of their runaway enthusiasm for whole grains and fiber. Whole grains, you see, will cure you of almost everything:
A moderate body of evidence from large prospective cohort studies shows that whole grain intake, which includes cereal fiber, protects against cardiovascular disease. Limited evidence shows that consumption of whole grains is associated with a reduced incidence of type 2 diabetes in large prospective cohort studies. Moderate evidence shows that intake of whole grains and grain fiber is associated with lower body weight.
Wowzers. Eat those whole grains, and you’ll avoid heart disease, diabetes and obestiy. To provide evidence for that paragraph, the committee cites a slew of observational studies showing an association between eating more whole grains and better health, and even tosses in a few clinical studies as well. If you didn’t know better, the evidence that whole grains are a cure-all would be convincing.
But I do know better. Several times, after seeing yet another news story about the wonders of whole grains, I’ve looked up the study that inspired the article. I’ve always found paragraphs like this one, from a study cited by the committee:
Behall (2006) compared the effects of feeding three whole-grain diets on blood pressure with weight as an ancillary outcome. Participants (n=25) consumed a controlled Step I diet for 2 weeks after which approximately 20 percent of energy was replaced with whole wheat/brown rice, barley, or half wheat-rice/half barley, for 5 weeks each.
The researchers apparently didn’t have the courtesy to tell us what kind of food was “replaced” with whole grains. I’ll bet you dollars to donuts (and you can keep the donuts) we’re talking about white-flour foods. That’s been the case in every other study I looked up — except when the researchers didn’t feel like being specific.
Now, let’s think about this … what happens when you remove white-flour foods and replace them with whole-grain foods in a clinical study? You lower the glycemic index and glycemic load of the meals. And unless the people in observational studies who report eating a lot of whole grains are sprinkling bran flakes on top of their donuts and white-bread sandwiches, they’re also consuming less white flour. Even goofball vegan doctors like Neal Bernard tell people to switch to whole grains specifically to reduce their glycemic load.
In other words, the many health benefits the committee ascribes to whole grains are probably the result of consuming less white flour — and thus reducing the blood-sugar blast from eating processed grains. If the committee is going to cite those studies as solid proof that whole grains are good, then they’re citing studies in which a reduced glycemic load was associated with better health.
Like I’ve said before, if I compare people who smoke filtered and unfiltered cigarettes, the people smoking filtered cigarettes will probably have lower rates of lung cancer. But that doesn’t mean filtered cigarettes prevent cancer. It means filtered cigarettes are less likely to cause cancer. Huge difference. If we really want to determine the benefits of whole grains, let’s compare people who eat them to people who don’t eat any grains at all.
Even if whole grains contain some beneficial nutrients, it’s crazy to recommend that all Americans should base their diets on them. Grains can cause all kinds of health problems. Loren Cordain has written extensively about how grains can cause leaky gut syndrome and lead to autoimmune disorders.
When I ate grains, I had arthritis. I had gastric reflux. I reached for the bottle of Pepto-Bismal at least once per week. When I was a traveling comedian, I always had Pepto-Bismal chewable tablets in my overnight bag. Now I literally can’t remember the last time I took Pepto-Bismal or an antacid. At the premiere party for Fat Head, the sound engineer told me that after the film convinced him to give up grains, he no longer needed his daily dose of Prilosec. He thanked me for changing his life. But according to the committee, he’s now at risk for heart disease and diabetes because he’s not eating his whole grains.
While the committee recommends that Americans cut back on sugar, they concluded that sugar doesn’t play any particular role in causing weight gain.
Added sugars, as found in sugar-sweetened beverages (SSB), are not different than other extra calories in the diet for energy intake and body weight. Thus, reducing intake of all added sugars, including sucrose, corn sweetener, fructose, high fructose corn syrup, and other forms of added sugars, is a recommended strategy to reduce calorie intake in Americans.
It’s all about the calories, you see. And yet elsewhere in the report, they state that people who eat a lot of sugar tend to consume more calories overall. Gee, do you think maybe there’s a connection there? Gaining weight may ultimately be caused by over-consuming calories, but then we have to ask ourselves what causes people to over-consume. Recent studies have shown that fructose depletes your body’s supply of ATP, the usable form of energy. When you’re low on energy, you’re going to eat more. Sugar is half fructose, while HFCS is 55% fructose. Put two and two together, and I’d say sugar and HFCS cause people to consume more calories.
Much of the report is dedicated to praising the benefits of fruits and vegetables. I don’t have anything against fruits and vegetables. I eat a lot of them, especially vegetables. I’m not convinced they’re the key to radiant health — there have been plenty of cultures where people were lean and healthy but rarely consumed plants foods — but if the committee wants to tell people to eat more vegetables, I don’t see any harm in it.
But I see plenty of harm in the committee continuing to recommend that we get most of our calories from carbohydrates, and of course that’s what they do.
Healthy diets are high in carbohydrates. Accepted Macronutrient Distribution Ranges (AMDR) for carbohydrates are 45 to 65 percent from carbohydrates. A maximal intake level of 25 percent or less of total energy from added sugars is suggested, based on trends indicating that people with diets at or above this level of added sugars are more likely to have poorer intakes of important essential nutrients. Active Americans should consume diets at the high end of the AMDR range (65%) while Americans on low calorie diets will need to consume diets at the low end of the range (45%).
That statement didn’t surprise me. It’s exactly what I expected. The surprise was that in a document full of praise for the Almighty Carbohydrate, the committee included this sentence:
The amount of dietary carbohydrate that confers optimal health in humans is unknown.
So there you have it: we don’t actually know how many carbohydrates people should eat to be healthy, but trust us … you should eat a LOT of carbohydrates.
And now, to pluck up everyone’s spirits a bit, I’m happy to report that a doctor who actually gets it was on TV: