Nutrition Myths
Can we trust dietary guidelines?


  • Dietary guidelines are influenced by politics, industry involvement and peer pressure to conform to the mainstream views among scientists. These factors and a growing concern that major health problems are increasing, created a sentiment of distrust towards official guidelines. This forced us to reach for other sources of information.
  • However, these alternative sources come from poor quality profit-driven media, as well as non-scientific or pseudo-scientific materials that are available on the internet.
  • We all like to make informed decisions, especially when it concerns our health and well-being.
  • This article discusses the factors that currently influence our food choices, what shapes the official dietary guidelines and why there is a growing trend to look for alternative answers.


Can we trust dietary guidelines?

Ideally, we should be able to make informed decisions on our food choices. However, where can we get the information from? Who can we trust to tell us what’s good and what’s not? Are dietary guidelines reliable?

Most people have little or no knowledge of biochemistry, nutrition science or medicine. Therefore, they rely on the official authorities to provide the necessary information or on so-called experts to bring some light on this convoluted subject.

Until recently, the dietary guidelines published by the authorities, such as the USDA in the U.S. or equivalent organizations in other countries, were the most trusted source of this information.

Unfortunately, this has changed in recent decades, mostly because of one of the biggest controversies that nutrition science has ever dealt with – the subject of dietary cholesterol, saturated fat and heart disease.

This highly controversial subject made many of us lose trust in the official sources and triggered in us a curiosity to look for alternative answers.

The questionable science behind the decisions that shaped the dietary guidelines also gave rise to the nutritional profession, a multitude of FAD diets, numerous bogus health claims related to nutrition and diet and the emergence of charlatans and quacks who seized the opportunity to make a lot of money on almost any diet or claims that are viewed as alternative.

Are dietary guidelines reliable?

The Dietary Guidelines for Americans, jointly released by the U.S. Departments of Agriculture (USDA) and Health and Human Services (HHS), are designed for professionals to help all individuals ages 2 years and older to consume a healthy, nutritionally adequate diet and to prevent chronic diseases. The Dietary Food Guidelines are published every 5 years, with the latest published in 2015.

Since 1980, the Dietary Guidelines have been the basis of USDA’s food guidance/symbols, including the more recent food guidance symbols (1984: Food Wheel, 1992: Food Guide Pyramid, 2005: MyPyramid, 2010: MyPlate).

Food guidelines are generally built on the scientific evidence, as USDA states:

Are dietary guidelines based on evidence?

The problem here is that the scientific data that supports those guidelines is not always sufficient or is simply non-existent, leading to decisions based on unsubstantiated assumptions. These decisions may not be necessarily based on science but influenced by politics or industry.

This was the case in the “saturated fat, cholesterol and heart disease” controversy which led to wrong decisions, some of them, unfortunately, with negative consequences on public health and on the reputation of those official authorities.

In practical terms, what does that mean?

Lets’ take the following example of cholesterol.

Dietary guidelines and major health organizations have been telling us, for four decades, that there are two major villains in the increased chance of developing cardiovascular disease:

  • dietary saturated fat
  • dietary cholesterol

Note: Salt and sugar were also included in this group, although with less emphasis when compared to the first two resulting in a long lasting anti-fat and anti-cholesterol campaign that continues to this date.

Only in 2015 (about 40 years after the guideline came out) the dietary guidelines committee, that is comprised of a group of specialists and advises the USDA, decided to scrap their previous recommendation that restricts dietary cholesterol intake, as shown in the following screen shot from the USDA website.

This was due to the clear evidence that dietary cholesterol doesn’t increase blood cholesterol. (1)

Recommendations not to restrict cholesterol in dietary guidelines

Just when you might think that this cholesterol subject would be finally solved, something unexpected happened.

Despite the recommendations given by the experts from the dietary guidelines committee (mentioned above), the official guidelines continue to include the dietary cholesterol limits, explaining that it comes together with high saturated fat foods.

Since saturated fats are recommended not to exceed 10% of total daily calories, cholesterol is expected not to exceed 300mg. (2)

Here is an extract taken from the USDA website:

Cholesterol recommendations as per current dietary guidelines

Therefore, after knowing that it took four decades for the USDA advisory to finally acquit dietary cholesterol, and then seeing these recommendations being ignored in the dietary guidelines, how can we trust their position on saturated fats? Perhaps saturated fat is also not harmful but will it take 30 years for them to inform us about this?

The hypothesis that dietary saturated fat and cholesterol increase the risk of heart disease has been accepted as a fact for the last four decades. It is still the main focus of the dietary guidelines.

Even coconut oil which is mainly made up of medium chain fatty acids, with distinct properties to saturated long chain fatty acids abundant in animal products, is still officially considered as harmful, while there is no evidence of that.

MCT oil, for instance, has been shown to have many benefits, yet it is almost entirely saturated.

However, scientific evidence of these claims has been lacking and it looks like we have been on the wrong path and following wrong diets for the last forty years.

Curiously, scientific evidence seems to play only some part of the decision making in drafting the dietary guidelines. Non-scientific factors usually dominate. Here are some examples:

  • Strong political involvement on the dietary guidelines

    The best example was the introduction of “Dietary Goals for Americans” in 1977 (by the U.S. Select Committee on Nutrition and Human Needs) that proposed a reduction in saturated fat, cholesterol and salt consumption and an increase in carbohydrate intake. (3)

    These guidelines were not based on the scientific evidence (no such evidence existed at the time), but merely on an unproven theory.

    These guidelines have been affecting millions of people worldwide to this day. The decision of introducing new guidelines was political and, not only ignored the lack of scientific evidence, but the warning from many scientists (e.g. Robert Olson, John Yudkin). You can watch the footage from the committee’s meeting in Tom Naughton’s documentary “Fat Head”

    Some call it the biggest uncontrolled nutritional experiment in the world’s history that was applied on the entire populations of several countries.

    This experiment, unfortunately, didn’t go very well, and the biggest proof is the epidemic of obesity, type 2 diabetes and cardiovascular diseases throughout western countries.

    This doesn’t not mean that we should have been stuffing ourselves with saturated fat and cholesterol.  However, if the focus of the dietary guidelines was on other food components such as sugar, trans fats and processed foods, we wouldn’t see the obesity epidemic that we are faced with today.

  • Influence of the industry on Dietary Guidelines

    The food industry often sponsors scientific studies, influencing their outcome and the decisions made based on them.

    Another good example of their influence is the revolving door policy between the FDA and the top management of the grain industry. The FDA’s policy makers often changed jobs and worked as top managers in the grain industry. (4)

    Non-surprisingly, the FDA was passing grants for studies that supported the FDA’s pro carbohydrate and anti-fat propaganda.

  • The scientific truth

    The “scientific truth” doesn’t always depend on the quality of the studies, but on the individual conducting the studies.

Scientists (and in recent years, outspoken journalists, or researchers) that oppose the conventional wisdom, are often regarded as heretics within the mainstream scientific world.

Presenting a new, challenging hypothesis or conducting studies that would contradict a widely accepted fact, is usually met with a sudden aggressive backlash, bullying and resentment from the mainstream and elites.

Many ( such as John Yudkin who believed that sugar not fat was the “bad” nutrient) backed down under the pressure.

Other more thick-skinned individuals, like Robert Atkins, withstood heavy criticism and never-ending attacks. His highly controversial, anti-establishment high fat diet and his extreme on the other end of the scale diet, became one of the most popular diets to this day.

So how do we decide what to eat? Which sources are available?

While the majority of people still follow the official dietary guidelines, there is a rapidly growing trend towards alternative views.

We are flooded by media reports, millions of opinionated websites, hundreds of dietary programs, books and science-naive celebrities. They all love to contribute bringing more and more confusion to the discussion.

There are four major factors that currently influence our decision on what to put on the plate:

  • Dietary guidelines – controversially the best source, some of the guidelines are compiled under the influence of politics, bad science and the food industry.

    History has shown that the guidelines did little to stop the rapidly growing obesity epidemic in western countries. However, this does not mean that all guideline recommendations are bad.

    It means that focusing on the irrelevant, unproven theories and ignoring major, well documented studies sends the wrong message to the public. For many years, most of us avoided butter and limited eggs and relaxed about margarine, potatoes, rice and bread. We were even relaxed about using sugar. Why?

    Because saturated fat and cholesterol were named our main health enemies. This is the main reason most products on supermarket shelves increased their sugar content while fat was drastically reduced.

  • Bad media coverage – can we really trust nutrition news? Media coverage allows the access for the majority of people to scientific information that they would otherwise miss or don’t understand.

    This democratized information gave the layman more tools to make decisions.

    However, the main goal of the media is to improve ratings and most of the time this means that the more sensational and shocking, the better.

    Most news on nutrition is either produced by journalists, with no basic scientific knowledge, who knowingly or unknowingly misinterpret the available studies.

    Other news presents only “out of context” part of the studies, (often not the most important), twisting or amplifying the interpretation of the results, just to make them more sensational.

    Shocking news suggesting compelling evidence will sell much better than boring information about a promising discovery that still lacks sufficient evidence.

  • Development of the internet – there is plenty of money to be made on the internet these days. Thousands of websites are written on nutrition, presenting conflicting views.

    The majority are only biased opinions, and do not have references to scientific sources or have references to sources that are not based on scientific evidence.

    Even those with proper references to scientific studies, sometimes present biased views, cherry picking studies to prove their own point of view and ignoring opposite views.

    But there are also some advantages.

    Through the websites with detailed references to scientific studies you can access the data, compare it against other well referenced websites and shape your informed opinions.

  • Ignorance – unfortunately we live in times where real science is being ignored. The best proof of these strange phenomena is visible in the latest political events, where governments from several countries use their power to control speech, shut down major science institutions and limit publicly available information sources for having opposite opinions.

People also chose to blindly believe and form opinions based on non-scientific information, rather than make informed decisions after considering all of the available scientific evidence.

There are several reasons why this happens. Analyzing scientific data can be boring (it’s true!) and we prefer already analyzed, easy to process information. There is just no time or patience for more.

To analyze scientific data, that is written in a scientific jargon is very time consuming and requires knowledge and equivalent/appropriate education.

Furthermore, it is so much easier to read a blog, most of the time from someone associated with the medical and/or nutritional world, with a very convincing and solid resume. These blogs tend to be especially attractive for the layman readers.

The blogs often present a one-sided point of view and extremely convincing arguments that don’t permit any doubt.

This is how so many movements, such as the paleo diet, alkaline diet and the gluten free diet, just to name a few, became so popular.

While these diets sound great, they are not based on solid scientific evidence. Some of them may actually work well for you, but not due to what they claim. Take any diet, remove added sugars, processed foods, fast foods and junk food, and use only a wide variety of whole foods and as long as you can stick to it, you will notice an amazing improvement in your health. That is the formula for a balanced and healthy diet, no matter what you name it.

In conclusion, this is the way to go!

If you don’t trust the mainstream nutrition, and prefer to choose the path of self-education, I would encourage you to, before making a decision on what dietary approach to adopt and who to trust, make sure that you first pick your sources carefully. Moreover, you should:

  • Reject anything that doesn’t have references to scientific studies
  • Follow the references to dig deeper for the information
  • Compare the information between various, well referenced sources
  • Take into account that although these source may be well referenced, they are usually biased and strongly support one point of view. Therefore, consider various, conflicting sources before forming your own opinion.

Following the USDA recommendation on restricting the saturated fat or cholesterol intake, not supported by scientific evidence, or following an advice from Jo’s blog on alkaline diet, which has never been shown to be valid, is definitely the wrong path to take.


You will find a summary of the most common nutrition myths and evidence-based nutrition facts here.

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