Nutrition Recommendations Constantly Change...Don't They?

I was on Facebook the other day, and someone in a group I'm in made a statement about not being sure whether to eat dairy, because "one week its bad, and the next its good". This is something I hear all too often from people: nutrition is complex, confusing, and constantly changing. One week 'X' is bad, the next 'X' is good. From an outsider's perspective, nutrition seems like a battlefield - low fat vs low carb vs Mediterranean vs Paleo vs Veg*n. Google any of these diets and you'll find plenty of websites saying that the government advice is wrong and they've got the perfect diet, the solution to all of your chronic woes, guarantee'ing weight loss, muscle growth, longevity, etc. Basically, if you've got an ailment, 'X' diet is the cure. I can certainly see this as being overwhelming from a non-scientist/dietitian perspective. Nutrition is confusing...right?

Screenshot, DGA: 1980, health.gov

From an insider's perspective, nutrition isn't all that confusing - every now and then we see paradigm shifts (like total fat/saturated fat, though even from the 1980 dietary guidelines, the controversy surrounding these was acknowledged). While I enjoy the debates that surround individual nutrients, and studying medical nutrition therapies, the reality, when it comes back to general food recommendations for the average person, bores me a bit, to be quite honest (the real challenge comes from working with the individual). The science of nutrients may evolve and change, but when we translate this back into food to prioritize, there's never really a dramatic shift. When it comes to normal nutrition (non-medical nutrition), very little regarding recommendations has changed over the years. Internet debates and the dietary Holy Wars can seem so interesting, but the reality remains that evidence-based dietary recommendations are anything but sexy.

If you look above at the tables, I made a comparison chart of the key points given by the Dietary Guidelines for Americans since they first began in 1980. There are some changes across time, primarily in the wording. More recent guidelines get a bit more complicated with their wording, as research has continued (e.g. guidelines to increase physical activity also now discuss reducing sedentary behavior). Depiction has also changed, moving from the FoodPyramid to MyPlate. The biggest thing you see is a minor change about total fat intake, reflecting the evolving research in this realm. What you can see are pretty clear, consistent recommendations - maintaining a healthy weight by balancing calories and staying physically active, eating nutrient dense foods by consuming a variety of fruits, vegetables, complex carbohydrates, low fat dairy, reducing or eliminate trans fat intake, consuming less saturated fat and sugar, reducing sodium intake, and limiting alcohol intake. More recent guidelines have emphasized the role of lean proteins and fish a bit more. They have also highlighted more pressing nutrients for the population to consider, like calcium/vitamin D, potassium, and dietary fiber.

Screenshot, DGA: 1980, health.gov

While the guidelines talk about restricting some nutrients, even going back to the first set in 1980, they were never meant for people to eliminate food groups- see the image to the left.

Screenshot, DGA: 1980, health.gov

While many have critiqued the low-fat recommendations, it only takes reading the 1980 guidelines quickly to see that reducing intake of high fat foods wasn't so that people ate more sugar/refined carbs (the guidelines specifically discuss choosing complex carbs and limiting sugars, though their main reason is to limit dental caries, and avoid excess calories). It even states that there shouldn't be a need for vitamin/mineral supplements, or to add fiber to foods that do not already contain it (pretty prescient looking back at these in a time when it seems like everything is enriched with vitamins and fiber - not hating on these practices, just an observation). Low fat meant a diet rich in fruits, vegetables, whole grains, legumes, and nuts.

You can debate small parts of the diet, and some extreme viewpoints will probably still see this diet as misguided, but to most, I imagine most of this sounds like good advice. If recommendations have stayed the same, why does nutrition come off as so confusing? I'd like to propose a few reasons, which may or may not apply to most individuals:

1. Bad Science/Health Reporting - Media fuels a lot of the confusion, in my opinion. Misleading headlines and highly biased reporting are my personal pet peeve. If you casually follow health news, or are in the health sciences and just read abstracts, you're not going to get the full story, and things are going to seem to constantly change. I've critiqued scientific news reporting before, either all out misleading readers with headlines, or trying to reduce specific foods/nutrients to a title of "good" or "bad". Everything in nutrition is about how much of it is consumed, and in the context of the total diet - when I teach Nutrition 101 students, this is something I harp on constantly. Also, any headline is likely reporting on one study- nutrition is a pretty soft science, and requires several lines of evidence before a clear picture can be formed. No one study is going to be a game changer, and most headlines won't be either.  (something I've always wondered - do health news reporters even have subscriptions to scholarly journals to read full studies? I've started to think about this with bloggers I see out there talking about science who don't disclose association with a university). 

2. Simple Marketing/Cherry picking Nutrients - things like 'low fat ice cream' never fell under the dietary guidelines or the recommendations as foods to regularly consume. Somehow in the translation from recommendations to practice, low-fat meant that anything without fat was healthy. Sure, that ice cream has less fat/calories in it, but it doesn't change the fact that it's dessert, it contains a lot of sugar, and relatively few other nutrients - all going against the guidelines. It seems like the fad diet movements inspired by cherry-picking specific nutrients from the guidelines, combined with food marketing was a perfect storm to make a ton of minimally nutritious products that confuse the hell out of consumers. 

3. Conspiracy Theories - In more modern nutrition, I constantly run into people (especially hearing it from students) that we can't trust recommendations because we can't trust the government. Literally, i have come across many a comment on forums/sites/articles where people seem to believe the government is trying to give us all diabetes with its recommendations. Besides a clear misunderstanding of the scientific evidence that backs the recommendations, this refusal to trust 'government sources of nutrition' is pretty unfounded. The Dietary Guidelines are set by a committee that consists of reputable scientists/clinicians, that take into account the commentary of the public.  The committee advises individuals to consume foods that achieve the optimal nutrient intakes based off of the the Institute of Medicine's recommendations, a non-governmental organization that sets the Dietary Reference Intakes for all of the nutrients. So many individuals are willing to pass off the recommendations set by some of the best PhD/MD/RD's in the country, and believe the word of someone writing a blog who told them those PhD/MD/RD's are wrong - are we so willing to accept any and all conspiracy theories nowadays?  If you were to follow all of the fad diets out there, you'd be left eating undomesticated leafy greens and large gusts of air on a remote island away from civilization.

For the average person, I'd hope that this clears up some confusion about nutrition recommendations. They aren't constantly changing dramatically, and rarely change at all over time. The core principles remain the same: maintain a healthy weight while eating a varied diet, high in fiber, rich in fruits, vegetables, dairy, complex carbohydrates, nuts, and some meat/poultry/fish - it's as simple as that. If you choose not to eat this, make sure to replace any nutrients you might be missing. I'm not trying to say that nutritional scientists/dietitians know everything, or that the guidelines are perfect for everyone, but if followed, they certainly won't be leading individuals down a path to nutrient deficiencies, and likely not to (preventable) chronic disease. Rather, the problem seems to be that no one follows the recommendations - see Colby Vorland's post on this here.

References:

http://www.health.gov/dietaryguidelines/

http://www.health.gov/dietaryguidelines/1980_2000_chart.pdf