Table of Contents
It has become common rhetoric for those promoting various types of diets to suggest that dietary guidelines published by government departments are at best, unhealthy, or at worst, causative in driving obesity and chronic disease in the population.
While different countries and organizations produce their own guidelines, with slight differences, most of the conversation has focused on the Dietary Guidelines for Americans, that are created by the USDA.
Often the claims is that following these guidelines actually harms health, rather than promote it. And the guidelines are simply a result of industry forces, long-standing bias, and shoddy science.
But do these claims hold up to scrutiny? In this episode Alan and Danny look at some of the arguments put foward, and take a look at the science underpinning dietary guidelines in a number of countries.
Public Feed Timestamps:
- [0.01.46] Examples of arguments put forward stating that it’s not healthy to follow dietary guidelines
- [0.12.50] History of the development of guidelines in the US & narratives around Ancel Keys
- [0.23.50] Misrepresentation of what the guidelines say
- [0.30.49] What are actually in the current Dietary Guidelines for Americans?
- [0.33.10] Changes to guidelines over time
- [0.36.05] Other countries’ guidelines: UK, Canada, Nordic countries
- [0.40.50] Investigating the rise in obesity/disease prevalence with the roll out of the guidelines
- [0.56.34] Do people follow the guidelines?
- [1.00.01] The negative role of the food industry
- [1.03.50] Potential issues with dietary guidelines
Premium Feed Timestamps:
- [0.00.46] Examples of arguments put forward stating that it’s not healthy to follow dietary guidelines
- [0.11.50] History of the development of guidelines in the US & narratives around Ancel Keys
- [0.22.50] Misrepresentation of what the guidelines say
- [0.29.49] What are actually in the current Dietary Guidelines for Americans?
- [0.32.10] Changes to guidelines over time
- [0.35.05] Other countries’ guidelines: UK, Canada, Nordic countries
- [0.39.50] Investigating the rise in obesity/disease prevalence with the roll out of the guidelines
- [0.55.34] Do people follow the guidelines?
- [0.59.01] The negative role of the food industry
- [1.02.50] Potential issues with dietary guidelines
- [1.10.18] Key Ideas segment
- 378: Nutritional Epidemiology
- 386: Deirdre Tobias, ScD – Study Design, Diet Collection Methods and Nutrition Epidemiology
- 428: Food Environments
- Review: Montani, 2021- Ancel Keys: The legacy of a giant in physiology, nutrition, and public health
- Lecture: Alan Flanagan – The Seven Countries Study: Facts Over Fiction (subscription required)
#1: Twisting of Narratives & Use of Partial Truths
Use of narrative the evokes emotion, has some aspect of truth to it, which is then used to get to conclusions that are just false…
Do guidelines typically recommend limits on fat intake? Sure; across guidelines, fat intakes of between 20 – 40% are generally suggested. But as we discussed, this is a function of aiming to keep saturated fat low, rather than dietary fat being unhealthy.
As an example, from the Nordic Nutrition Recommendations: “The current scientific evidence used to set recommended intake ranges is strong for certain sub-categories of macronutrients but less so for the intake of total carbohydrates and fat. The scientific evidence for the fatty acid composition in the diet is stronger than for the total fat intake with respect to development of chronic diseases such as coronary heart disease, type-2 diabetes, and certain cancers.”
But then the dietary fat limit is used to justify odd claims like: “they want you to consume sugar instead”. Often there is mention of sugar industry lobbying, etc.
But what guidelines recommend more added sugar? Where can this be found?
As Alan noted in the episode, this is conflating guidelines with what the food industry has done. So are there zero-fat yogurts with added sugar? Sure. But no guideline recommends people to eat an excess of added sugar.
#2: Revisionist Framing & Outright False Claims
The revisionist nature of this. I won’t recap all Alan has said here, and in other episodes on the Ancel Keys demonisation.
See this review for more context: Montani, 2021- Ancel Keys: The legacy of a giant in physiology, nutrition, and public health
#3: Are some “anti-dietary guidelines” arguments valid?
- COIs: In relation to the US, there is a conflict of interests due to the USDA having a role in developing nutrition guidelines whilst also being tasked with helping the agricultural industry.
- Food industry role: The role of the food industry in shaping population intake is a problem
- Original recommendations are too harsh on dietary fat: Perhaps, but since then more nuance has been added (e.g. focus on sat fat; while total fat and cholesterol are less of a focus).
- Sugar limits still too high: This is a fair point, but some committees advising government guidelines already discuss this. For example, in the UK, the Scientific Advisory Committee on Nutrition (SACN) advice is to limit free sugars to no more than 5% of daily calorie intake.
Detailed Study Notes
Examples of Arguments/Claims
In an opinion piece published in 2016 in JAMA, Dr. David Ludwig states:
- “As a result of these efforts, dietary fat decreased to near the recommended limit of 30% total energy. But contrary to prediction, total calorie intake increased substantially, the prevalence of obesity tripled, the incidence of type 2 diabetes increased many-fold, and the decades-long decrease in cardiovascular disease plateaued and may reverse, despite greater use of preventive drugs and surgical procedures.”
- “Recent research suggests that the focus on dietary fat reduction has directly contributed to this growing burden of chronic disease.”
At the start of the episode, five clips are played, showing the claims made by a prominent “anti-guidelines” figure, author Nina Teicholz. The original clips are primarily taken from an interview available on YouTube (timestamps linked below):
- Interview on ReasonTV – How Big Government Backed Bad Science Made Americans Fat
- [4.32 – 5.22] – “I read every single study that the guidelines are based on, and couldn’t find any rigorous evidence for them”
- [7:01 – 7:21] “there is no rigorous evidence that eating more fruits and vegetables promotes health” – demand for RCTs
- [9.20 – 09.51] Sugar, grains, vegetable oils – cookies, crackers, chips:: “and the guidelines promote that”
- [10:22 – 10.50] Limits on saturated fat, salt, etc. are just long-standing biases, Ancel Keys, blah blah blah
In addition, I mentioned the following line from Teicholz’ book (found on page 137): “In short, to avoid fat, people should eat sugar, the AHA advised”.[Additional reading: This is a nice, short blog entry from the excellent Marion Nestle. In relation to Teicholz’s work she states: “It does little to foster the health of the public to make nutrition science appear more controversial than it really is.”]
What are “the guidelines”?
“Food-based dietary guidelines (also known as dietary guidelines) are intended to establish a basis for public food and nutrition, health and agricultural policies and nutrition education programmes to foster healthy eating habits and lifestyles. They provide advice on foods, food groups and dietary patterns to provide the required nutrients to the general public to promote overall health and prevent chronic diseases.”
“More than 100 countries worldwide have developed food-based dietary guidelines that are adapted to their nutrition situation, food availability, culinary cultures and eating habits. In addition, countries publish food guides, often in the form of food pyramids and food plates, which are used for consumer education.”
“National food-based dietary guidelines (FBDGs) provide context-specific advice and principles on healthy diets and lifestyles, which are rooted on sound evidence, and respond to a country’s public health and nutrition priorities, food production and consumption patterns, sociocultural influences, food composition data, and accessibility, among other factors.”
“Typically, FBGDs propose a set of recommendations in terms of foods, food groups and dietary patterns to provide the required nutrients to promote overall health and prevent chronic diseases. Yet, many countries are now moving towards more holistic perspectives by addressing food combinations (meals), eating modalities, food safety considerations, lifestyle and sustainability aspects in their FBDGs.”
The FAO has a list of different countries’ guidelines available here.
However, as noted in the episode, most of the online nutrition debates around the impact of “the guidelines” is in reference to the Dietary Guidelines for Americans, published by the United States Department of Agriculture (USDA).
Others that were mentioned in the episode include:
“The dietary guidelines are virtually identical in every country in the world” – quick visual overview from this blog post by Kevin Bass.
US: Dietary Guidelines for Americans
History of the US Guidelines
1977 US Senate committee report Dietary Goals for the United States.
Followed by the first USDA guidelines: The 1980 Dietary Guidelines for Americans (one of the earliest such national guidelines).
This appendix shows the key recommendations from each set of dietary guidelines released, showing how they evolved and what aspects remained consistent.
The timeline for the development of the guidelines, and where nutrition science was at the time, is important to put into context.
- Note that the first US guidelines (1980) were made off the back of that 1977 report.
- The early studies from Ancel Keys and colleagues were done in the post-World War II period (1950 – 1970), when nutrition science was only beginning to shift from focusing on eradicating nutrient deficiencies to instead looking at chronic disease risk.
- Work by the likes of Ancel Keys, Frederick Stare, and Mark Hegsted, started to highlight the potential role of dietary fat (or later, more specifically saturated fat) in being a major contributor to heart disease, via the ability to raise serum cholesterol and LDL-cholesterol.
- While some researchers, such as John Yudkin, were pointing to sugar, the level of accumulating evidence for the role of dietary fat subtypes in CVD risk was ahead of the evidence on the harms of sugar.
- Therefore, to say anything untoward was going on by having a focus on serum cholesterol and dietary fat, completely ignores where nutrition science was at the time. Not to mention, how incredibly consistent much of these findings have been (with added refinement over time).
The most current set of guidelines in the US are the Dietary Guidelines for Americans 2020 – 2025.
Dietary Guidelines for Americans 2020 – 2025 provide four overarching Guidelines:
- Follow a healthy dietary pattern at every life stage.
- Customize and enjoy nutrient-dense food and beverage choices to reflect personal preferences, cultural traditions, and budgetary considerations.
- Focus on meeting food group needs with nutrient-dense foods and beverages, and stay within calorie limits.
- Limit foods and beverages higher in added sugars, saturated fat, and sodium, and limit alcoholic beverages.
There is a focus on dietary patterns. The Guidelines “explicitly emphasize that a healthy dietary pattern is not a rigid prescription”. In fact, they contain a customizable framework which can allow for personal, cultural, and traditional preferences. There are examples including omnivorous, vegetarian and Mediterranean patterns.
From a food/nutrient level, there recommendations are unsurprising:
- Focus on: fruits, vegetables, grains, dairy, “protein foods”, oils (veg oils, nuts, seeds)
- Limit: added sugars, sat fat, sodium, alcohol
- Most of population over-consumed refined grains, and under-consume whole-grains
UK EatWell Guide
In the UK, the government has published healthy eating recommendations (see this document), based of suggested energy and nutrient intakes for the general population (see here). These are based on the recommendations of the Committee on Medical Aspects of Food Policy (COMA) and the Scientific Advisory Committee on Nutrition (SACN).
The Eatwell Guide is a visual representation of these recommendations. It replaced the previous image of the “eatwell plate”.
The Eatwell Guide is based on the 5 food groups and shows how much of what you eat should come from each food group.
Some key recommendations:
- Over a third of the diet should come from fruit and vegetables.
- Eat at least 5 portions of a variety of fruit and vegetables every day.
- Limit the consumption of 100% fruit and vegetable juices and/or smoothies to a combined total of 150ml (one portion) per day
- Base meals on potatoes, bread, rice, pasta or other starchy carbohydrates; choosing wholegrain versions where possible.
- Have some dairy and alternatives; choosing lower fat and lower sugar options.
- Beans, peas and lentils (which are all types of pulses) are good alternatives to meat because they’re naturally very low in fat, and they’re high in fibre, protein, vitamins and minerals.
- Limit the intake of products such as chocolate, cakes, biscuits, full-sugar soft drinks, butter, cream and ice-cream, to infrequent consumption.
Again, looking at such recommendations, it highlights why claims about guidelines promoting sugar or processed foods are such strange and inaccurate claims.
Canada Food Guide
You can see Canada’s Food Guide here.
In addition to the foods, they recommend:
- Be mindful of your eating habits
- Cook more often
- Enjoy your food
- Eat meals with others
- Use food labels
- Limit highly processed foods
- Marketing can influence your food choices
Some examples of diet guidelines in Canada’s Food Guide:
- Include plenty of vegetables and fruits in your meals and snacks. Try making half of your plate vegetables and fruits.
- Whole grain foods are a healthier choice than refined grains because whole grain foods include all parts of the grain.
- Use food labels to choose foods that have less sodium, sugars or saturated fat.
- Plant-based protein foods can provide more fibre and less saturated fat than other types of protein foods.
The Food Guide does a great job of giving practical examples of how to achieve each of the recommendations in the above image.
Nordic Nutrition Recommendations
The Nordic Nutrition Recommendations form the basis for nutrition policies and dietary guidelines in Norway, Sweden, Finland, Iceland, Denmark, the Faroe Islands and Greenland.
The first edition of the NNR was published in 1980, with the most current version at the time of this podcast episode being published in 2012. However, a new updated NNR is due in 2022.
The recommendations promote an overall micronutrient-dense dietary pattern with a set of food selection changes (see table below), that includes that following fundamental tenets:
- Decrease energy density, increase micronutrient density, and improve carbohydrate quality.
- Improve dietary fat quality by balancing the fatty acid proportions.
- Limit processed and red meat.
- Limit the use of salt in food products and food preparation.
Intakes of fibre, dietary fat, saturated fat, added sugars, etc. are largely in line with those seen in US Dietary Guidelines.
Do the guidelines cause obesity and chronic disease?
As Stephan Guyenet has highlighted previously, if this claim were accurate, then there are a number of predictions that come from such a hypothesis that would have to be supported by good evidence. Five predictions Guyenet outlines are:
- There should be a correlation between the publication of the Dietary Guidelines and the obesity epidemic
- Americans should have reduced our fat intake in response to the Guidelines
- Low-fat diets should cause weight gain
- People who followed the Guidelines should have gained more weight than people who didn’t
- Other countries with dissimilar dietary guidelines should not have a similar obesity problem
All five of these predictions fail when we look at the current evidence base.
Guyenet: “Although the low-fat diet doesn’t appear to be a silver bullet for our national weight problem, the hypothesis that US Dietary Guidelines caused the obesity epidemic by reducing our national fat intake has more holes in it than Swiss cheese on baguette.”
Do people actually follow guidelines?
In the UK:
- Cardiovascular disease risk REduction Study (CRESSIDA)
- Randomized controlled trial of 165 healthy, non-smokers
- Adherence to the dietary advice was confirmed from dietary records and biomarkers of compliance.
- Selecting a diet consistent with current dietary guidelines lowers BP and lipids, which would be expected to reduce the risk of CVD by one-third in healthy middle-aged and older men and women.
- Fruit & veg portions per day:
- adults = 4.2
- 65- to 74-year-olds = 4.3
- teenagers = 2.7
- Who meets the 5 A Day recommendation for fruit and vegetables?
- 31% of adults
- 32% of 65- to 74-year-olds
- 8% of teenagers
- Fibre intake in adults is 19g per day, (recommendation = 30g per day)
In the United States:
- There is literally a section in the 2020-2025 Dietary Guidelines called “Most Americans Do Not Follow a Healthy Dietary Pattern”
- The Healthy Eating Index (HEI) is a measure of diet quality (on a scale from 0 to 100) that can be used to assess compliance with the Dietary Guidelines.
- Average diet quality is scored at 59, showing recommendations are far from being met.
- Differences in overall HEI scores are seen across age, sex, race-ethnic, and income subgroups and by pregnancy and lactation status, though poor diet quality is observed across all groups.
- Fibre: 90% of women and 97% of men do not meet recommended intakes
- 85% of Americans under-consume fruits, vegetables, & whole grains
“Poor compliance with the Guidelines, rather than the guidelines themselves, is likely responsible for the weight gain observed in the American population. Adoption of an eating pattern consistent with the Dietary Guidelines should facilitate population weight control if sustained long term.” – Quatromoni et al., 2006
- Ewers et al., 2021 – Non-adherence to established dietary guidelines associated with increased mortality: the Copenhagen General Population Study
- “Non-adherence to Danish food-based dietary guidelines is associated with up to 43% increased all-cause mortality in a dose–response manner.”
Could Guidelines Be Improved?
Could the added sugar limits be lower?
- On the basis of their ‘Carbohydrates & Health Report’, SACN recommends that:
- Free sugars* should account for no more than 5% daily dietary energy intake.
- Free sugars = those added to food or those naturally present in honey, syrups and unsweetened fruit juices, but exclude lactose in milk and milk products.
- The consumption of sugar-sweetened beverages (e.g. fizzy drinks, soft drinks and squash) should be minimised by both children and adults.
- * The term “free sugars” is now used rather than older terms such as “Non-Milk Extrinsic Sugars” (NMES) or “added sugars”.
- Free sugars* should account for no more than 5% daily dietary energy intake.
Is dairy promoted as more essential than it should be?
- The US guidelines have statements such as “healthy dietary patterns feature dairy…”
- However, they do include fortified soy products in the dairy category.
- Other countries, perhaps most notably Canada, have explicitly stated dairy as something completely optional to include or not.
The types of rhetoric used and claims made in relation to the conspiratorial nature of dietary guidelines, is perhaps best summarised In their history of science piece titled ‘Was there ever really a “sugar conspiracy”?’, published in Science in 2018, Johns & Oppenheimer write:
“… allegations have been made against the sugar industry, with claims that prominent industry-backed researchers in the 1960s downplayed or suppressed evidence linking sugar and heart disease. Building on a newly popular narrative holding that the low-fat campaign of the 1980s was not based on solid science, these allegations have suggested that if not for the machinations of the sugar industry and its cadre of sponsored researchers, the history of U.S. dietary policy might have unfolded very differently. In this article, we argue that the historical evidence does not support these claims. Although we do not defend the sugar industry and cannot address every aspect of this history, we believe recent high-profile claims come from researchers who have overextended the analogy of the tobacco industry playbook and failed to assess historical actors by the norms and standards of their time. Our analysis illustrates how conspiratorial narratives in science can distort the past in the service of contemporary causes and obscure genuine uncertainty that surrounds aspects of research, impairing efforts to formulate good evidence-informed policies. In the absence of very strong evidence, there is a serious danger in interpreting the inevitable twists and turns of research and policy as the product of malevolent playbooks and historical derailments.” – Johns & Oppenheimer, 2018