The Dietary Guidelines for Americans 2015-2020
The new Dietary Guidelines for Americans have just been released – they’re supposed to be good till 2020, when the process will be repeated. This document will undoubtedly influence (or rather, be used to support) the dietary guidelines for this country. And it’s not just a question of advice that you’re welcome to ignore if you find it unwelcome – any funding for food in federal prisoner, school, mental health facilities, or welfare food programs is tied to some interpretation of the guidelines.
With that degree of control and influence, and with all the cost and fanfare of producing the Guidelines, you wouldn’t expect to find obvious mistakes in them. Compare this to submitting an article to be peer-reviewed before publication in a medical journal. If anything you say isn’t clear, isn’t solidly backed up by the evidence you cite, is contradicted by other evidence, is inconsistent, or is just not understood by a reviewer, it won’t get published. Actually, all sorts of rubbish gets published, the system isn’t perfect, and people whose views don’t contradict the consensus generally get a much easier ride. Which seems unfair, and is annoying, but actually works in favour of the low carb movement at present, because nothing we get to publish is ever allowed to be junk.
The best pre-publication peer-review the Dietary Guidelines recieved came from Nina Teicholz in the BMJ. Read the letters too. It doesn’t seem as if any of this criticism was taken on board, which is a real pity. In our opinion, informed criticism from someone with time to spare on your work is always valuable, one way or another.
The unscientific low-fat dairy fetish will not die
So right off there seems to be one glaring, unarguable, and completely avoidable mistake in the guidelines, because they go on and on about low-fat dairy. Full-fat dairy is not part of a healthy dietary pattern (even though Americans don’t eat enough dairy according to the DGAC and the dairy lobby). The trouble is, everyone knows by now that full-fat dairy isn’t associated with any more disease than low-fat diary, and is usually associated with less. This is so uncontroversial that we shouldn’t even feel the need to reference it. But here’s a study from New Zealand, a meta-analysis of randomized controlled trials (RCTs) in which people were told to eat extra dairy. The people who ate low-fat dairy gained more weight than the people who were told to eat full-fat dairy. Here’s a study of fat and type 2 diabetes risk (an observational study of 14.000 people followed for 14 years) using a 7-day food diary, which is a more accurate tool than the food frequency questionnaires (FFQs) the DGAC process largely relies on for its observational evidence; “Total intake of high-fat dairy products (regular-fat alternatives) was inversely associated with incident T2D (HR for highest compared with lowest quintiles: 0.77; 95% CI: 0.68, 0.87; P-trend < 0.001). Most robust inverse associations were seen for intakes of cream and high-fat fermented milk (P-trend < 0.01) and for cheese in women (P-trend = 0.02). High intake of low-fat dairy products was associated with increased risk, but this association disappeared when low- and high-fat dairy were mutually adjusted (P-trend = 0.18). Intakes of both high-fat meat (P-trend = 0.04) and low-fat meat (P-trend < 0.001) were associated with increased risk.” (This last sentence was only true when processed meat was included – fatty red meat wasn’t associated with diabetes at all). And here’s a study using biomarkers of dairy consumption, the most reliable measure of all, to see if dairy fat was associated with heart disease. “Odd chain PFA (15:0, 17:0) concentrations were significantly inversely associated with CHD (OR 0.73, 0.59–0.91, p<0.001, Q4 versus Q1).”
The DASH diet was one of the scientifically tested diets used as part of the evidence base for the “Healthy diet patterns” in the guidelines. It’s a low-fat, low saturated-fat diet high in potassium, antioxidants and fibre from wholegrains, fruits, and vegetables, with low-fat dairy as a protein source. The DASH diet is effective for lowering blood pressure.
This study has just been released (by Ron Krauss’s research group) – it compares the standard DASH diet with a modified DASH diet in which full-fat dairy replaces low-fat (HF-DASH). The diet is now higher in saturated fat. If anything, it seems to be better for you.
Results: Thirty-six participants completed all 3 dietary periods. Blood pressure was reduced similarly with the DASH and HF-DASH diets compared with the control diet. The HF-DASH diet significantly reduced triglycerides and large and medium very-low-density lipoprotein (VLDL) particle concentrations and increased LDL peak particle diameter compared with the DASH diet. The DASH diet, but not the HF-DASH diet, significantly reduced LDL cholesterol, HDL cholesterol, apolipoprotein A-I, intermediate-density lipoprotein and large LDL particles, and LDL peak diameter compared with the control diet.
Conclusions: The HF-DASH diet lowered blood pressure to the same extent as the DASH diet but also reduced plasma triglyceride and VLDL concentrations without significantly increasing LDL cholesterol.
So why is there only low-fat dairy in the Guidelines? It’s just not as good as full-fat dairy. Most likely full-fat dairy has to go because some Americans are still eating “too much” saturated fat (the limit in the dietary guidelines is still 10% of energy) and telling all Americans to avoid full-fat dairy is an easy way to try to limit the saturated fat intake of the recidivists. The trouble with that logic is that you’re hitting the target, which is only a number, by avoiding some of the healthiest saturated fat-rich food in the diet. This is not good sense, and the Dietary Guidelines don’t even discuss the issue in a way that would let people make up their minds. If we can discuss it here, why couldn’t the DGAC also present the pros and cons of full fat dairy? (Cons – more calories. Pros – doesn’t cause more weight gain. Cons – might raise cholesterol. Pros – probably causes less heart disease. And so on. Not that hard.)
In fact, the guidelines are so verbose and pompous (“Follow a healthy eating pattern across the lifespan”) that they will be illegible to most Americans anyway – so the authors might as well have treated their readers like adults and given them more facts, a nuanced discussion and the power to make an informed choice.
How NOT to treat nutritional deficiencies
The 2015-2020 Dietary Guidelines lists some nutrients that Americans are underconsuming and likely to be deficient in – including iron (in women), choline, vitamin A, and vitamin D. These are nutrients best found in fatty foods of animal origin. These are the foods the DGAC think that Americans are eating too much of (so why is deficiency of these nutrients so widespread?). This section then tells people to get these missing nutrients by eating more fruit and veges and whole grains and low-fat dairy.
“In addition to helping reduce chronic disease risk, the shifts in eating patterns described in this chapter can help individuals meet nutrient needs. This is especially important for nutrients that are currently underconsumed. Although the majority of Americans consume sufficient amounts of most nutrients, some nutrients are consumed by many individuals in amounts below the Estimated Average Requirement or Adequate Intake levels. These include potassium, dietary fiber, choline, magnesium, calcium, and vitamins A, D, E, and C. Iron also is underconsumed by adolescent girls and women ages 19 to 50 years. Low intakes for most of these nutrients occur within the context of unhealthy overall eating patterns, due to low intakes of the food groups—vegetables, fruits, whole grains, and dairy—that contain these nutrients. Shifts to increase the intake of these food groups can move intakes of these underconsumed nutrients closer to recommendations.”
In many cases that is not going to help at all. Wholegrains don’t contain iron or vitamin D, or anything on the list except fibre and minimal traces of vitamin E and choline, but they do contain phytates that block absorption of iron and vitamin D. This doesn’t matter at all if your diet also contains foods that supply adequate iron and vitamin D3 – red meat and fatty animal foods. While it’s true that green veges and lentils supply some iron, and mushrooms supply a little vitamin D2, you will find higher rates of deficiency in people relying on these non-animal sources alone.
Eggs, fish roe, and liver are the best sources of choline. They’re all also foods that are rich in cholesterol – didn’t this set of Dietary Guidelines lift the limit on dietary cholesterol?
Only in the sense that they no longer include a recommended limit in mg/day. The Guidelines do, however, say “individuals should eat as little dietary cholesterol as possible”. So if anything, the recommendation is for reduced intake of cholesterol. And therefore, de facto, for a decreased intake of choline too.
The advice in the guidelines often seems contrary to the basic principles of good nutrition (and don’t get me started on the lack of useful advice for obese and diabetic Americans).
If you talk about Americans having problems with iron and choline deficiency, and you don’t suggest eating red meat and eggs as the way to fix these, you’ve flunked Nutrition 101. You should not have the job of composing dietary guidelines, just as someone who doesn’t know (or isn’t willing to write) that Napoleon became the leader of France in the aftermath of the French Revolution shouldn’t have the job of writing history books.
The Dietary Guidelines for Americans Committee has reached Peak Oil
The Guidelines also state that Americans eat diets that are too low in oil.
“About three-fourths of the population has an eating pattern that is low in vegetables, fruits, dairy, and oils.”
Well lots of people don’t tolerate lactose or casein, and lots more have been scared off cheese by previous DGAC announcements. I dare say that Americans might have higher dairy intakes if they were allowed to eat full-fat dairy and had better access to unprocessed, unadulterated dairy foods.
I checked and per capita US vegetable oil consumption in 2009 was 36 Kg, making an average of almost 100g/day (or 900 calories).
Even if much of this is deep fryer waste, it does not represent a diet low in oil. The Dietary Guidelines discussion of oil does not mention the use of oils in deep fryers or their presence in French fries and donuts at all. I am forced to conclude that the DGA Committee still does not know what it is talking about, even after robust criticism from Nina Teicholz and countless others.
The American diet is high in oil (mostly soybean oil) by global standards. Americans have high rates of chronic diseases. There is no evidence that intakes of oils in excess of the amounts currently consumed by Americans will promote health (the Guidelines do not discriminate between extra virgin olive oil and solvent extracted seed oils). From the LCHF point of view, it is very unlikely that someone eating a palatable high fat diet will become deficient in unsaturated fats; there is no need to seek them out in the form of solvent-extracted oils. In evolutionary terms, it seems highly unlikely that novel, industrially manufactured foods are essential for optimal human health.
What of the methods? Are they scientific?
The new focus of the DGA is, supposedly, on “eating patterns, not foods or nutrients”.
“the eating pattern may be more predictive of overall health status and disease risk than individual foods or nutrients. Thus, eating patterns, and their food and nutrient components, are at the core of the 2015-2020 Dietary Guidelines for Americans. The goal of the Dietary Guidelines is for individuals throughout all stages of the lifespan to have eating patterns that promote overall health and help prevent chronic disease.”
The DGAC has only looked at the evidence for 3 eating patterns (Healthy U.S.-Style Eating Pattern, Healthy Mediterranean-Style Eating Pattern, and Healthy Vegetarian Eating Pattern). You’ll notice that these patterns are all Healthy, and that none is traditional – they are only cuisines in the sense that Scientology is a religion. If you’re Paleo or LCHF or eat in any other way outside the box, the possibility that you have a healthy eating pattern is of no interest to them. That’s because your “eating pattern” contains foods (fatty red meat, full-fat dairy, coconut oil) or nutrients (saturated fat, cholesterol, salt) that they don’t accept as a part of any healthy eating pattern. So the healthy eating pattern rubric is still a way of focusing on single foods and single nutrients, just while pretending to do something else.
Science is the logical discussion of what can be quantified. The most accurate methods for quantification are the best. The most time-proven methods, all else being equal, will be better than novel ones, at least for a time. Dietary patterns are a new concept and cannot be as clearly quantified as nutrients, nor can their effects be detected very clearly at all. Analyzing the associations from exchanging one source of energy with another (“replacing 5% of energy from saturated fat”) is also a novel method that has never been robustly critiqued and the value of which is not clear (it’s only 6 years old). There is not a lot of reliable quantification going on and not a lot of logical discussion – what discussion there is, is either tautological or seems to be directed at arriving at some pre-determined point. That, and the lousy style, makes the thing harder to read than it needs to be.
What did the DGAC get right?
This: “Additionally, healthy eating patterns can be flexible with respect to the intake of carbohydrate, protein, and fat within the context of the AMDR.” Except of course that only unsaturated oils (not coconut oil) can be used to adjust fat intake, and the AMDR sets a minimum carb intake of 130g/day. But still, an improvement that could help many, were it clearly expressed. Unfortunately, it’s not; I had to dig up the paper referenced to understand the meaning of this passage.
A limit of 10% energy on added sugars. That’s added sugars, not bananas, fruit juice, or dried fruit. So although it looks like the 10% limit on saturated fat, it allows a lot more sugar in the diet (if the 10% limit on saturated fat only applied to added fat it wouldn’t have the harmful effect it does on the quality of the diet). The Dietary Guidelines even say “Beverages that are calorie-free—especially water—or that contribute beneficial nutrients, such as fat-free and low-fat milk and 100% juice, should be the primary beverages consumed.” (Fruit juice is a “nutrient dense beverage” in the parlance of the Guidelines.) But still – if people start to avoid added sugars they avoid many other poor-quality foods and ingredients that associate with added sugars. People will likely benefit from this, and, just as importantly, few will be harmed.
It’s okay to drink coffee now. I don’t know why we needed dietary guidelines to tell us this. Like a lot of things, coffee is fine if you like it and have some control over your intake. If you don’t or you haven’t, you might think differently.
Fruit and vegetables are pushed heavily, no-one thinks this is a bad idea.
There’s a recommended intake of grains, and at least half of those should be whole grains. The system is a complicated one of ounce-equivalents, 8 a day for men, but surely if you believe in wholegrains you don’t actually want people to eat refined grains just to keep up some imagined grain requirement, which is probably only there to keep fat at bay.
I despair at the use of “ounce equivalents”, “cup equivalents” and so on. I fear that no-one will ever actually use this system, and that it will merely serve to bamboozle. Perhaps MacDonald’s can be persuaded to use it in their menus.
Of course there is no useful discussion of diabetes or obesity.
“Calorie intake over time, in comparison to calorie needs, is best evaluated by measuring body weight status. The high percentage of the population that is overweight or obese suggests that many in the United States overconsume calories.”
Maybe in 2020?
I’m sure there’s more. The collected labours of so many educated people will surely have turned up more of value, and I haven’t read the whole document yet. I can’t imagine very many people want to. And that’s part of the problem. The elements of healthy eating shouldn’t be so complicated. Even though the guidelines contain a 5-point summary, which are meant to be simple and reasonable (presumably), few of these points are clear enough without going into the detailed discussions, (Lifespan? Recommended amounts? Nutrient dense beverages? Calorie Limits? Consume an eating pattern? Sodium? Food groups? Amounts that fit? What are these?) and even then…
The Dietary Guidelines for Americans 2015-2020 – Summary.
 Follow a healthy eating pattern across the lifespan. All food and beverage choices matter. Choose a healthy eating pattern at an appropriate calorie level to help achieve and maintain a healthy body weight, support nutrient adequacy, and reduce the risk of chronic disease.
 Focus on variety, nutrient density, and amount. To meet nutrient needs within calorie limits, choose a variety of nutrient-dense foods across and within all food groups in recommended amounts.
 Limit calories from added sugars and saturated fats and reduce sodium intake. Consume an eating pattern low in added sugars, saturated fats, and sodium. Cut back on foods and beverages higher in these components to amounts that fit within healthy eating patterns.
 Shift to healthier food and beverage choices. Choose nutrient-dense foods and beverages across and within all food groups in place of less healthy choices. Consider cultural and personal preferences to make these shifts easier to accomplish and maintain.
 Support healthy eating patterns for all. Everyone has a role in helping to create and support healthy eating patterns in multiple settings nationwide, from home to school to work to communities.
We had a go at this sort of thing a while back. It’s not easy, that’s for sure. Here’s our version from April 2014. We might issue revised guidelines every 5 years just in case. There are still some clunky lines here, but there is (we hope) nothing you’ll need to look up to understand.
The Real Food Guidelines.
 Enjoy nutritious foods everyday including plenty of fresh vegetables and fruit.
 Buy and prepare food from whole unprocessed sources of dairy, nuts, seeds, eggs, meat, fish and poultry.
 Keep sugar, added sugars, and processed foods to a minimum in all foods and drinks.
 If you drink alcohol, keep your intake low. Don’t drink if you are pregnant or planning to become pregnant.
 Prepare, cook, and eat minimally processed traditional foods with family, friends, and your community.
 Discretionary calories (energy foods) should:
- a) Favour minimally refined grains and legumes, properly prepared, over refined or processed versions, and boiled or baked potatoes, kumara or taro over deep fried or processed potato fries and chips.
- b) Favour traditional oils, fats and spreads over refined and processed versions.
P.S. There is a great discussion of the Dietary Guidelines, especially their sociological aspects, on Eathroplogy.