Before the invention of cows, cheeseburgers or even bread, the world didn’t seem to require a dietary guideline manual. Fast forward to today, and tweaks to these guidelines feel like a daily occurrence. In this article, we take a look at the history of dietary guidelines and how they’ve changed with the times. From ancient Athens to the Industrial Revolution, the guidance has steadily evolved to match our changing understanding of the human body, health and wellbeing. Buckle up – it’s a wild ride through the history of dietary guidelines, charting the fascinating developments in our understanding of what we should or shouldn’t eat.
The Early History of Dietary Guidelines
Early dietary practices and principles
Long before the advent of modern food guides, ancient peoples began to contemplate how to eat to promote good health. Ancient Egyptians recorded the value of variety and the avoidance of excess, while ancient Greeks advocated the idea that moderation should be observed in all aspects of life, including food.
First known dietary guidelines in history
Although we can’t be sure, the oldest dietary guidelines known to us were prescribed by ancient China. The Yellow Emperor’s Classic of Internal Medicine is generally dated to the second century BCE. It explains to the ancient Chinese emperor the ‘beneficial and injurious natures of the varied foods; the distribution of the five flavours to the five organs; and differentiating between the balanced and unbalanced in dietary therapy.’ The text divides foods into five types, based on their energetic properties, and recommends balanced eating, as follows:
Understanding dietary needs in the ancient world
Older dietary wisdom was often based on anecdotal findings and traditional observation. For example, prior to the contemporary era of nutritionised healthcare, the Ayurvedic system of dietary and lifestyle advice in ancient India was based on individual constitution. Classical dietary advice often utilised the notion of the ‘one size fits all’ approach. Hippocrates in ancient Greece is known for saying: ‘Let food be thy medicine and medicine be thy food.’
Dietary Guidelines in the Medieval Period
Influence of religion on dietary habits
Dietary habits under the reign of a religion could lead to quite different food opportunities. For instance, fasting on certain days, and giving up meat during Lent is a crucial part of the dietary regime observed in Christianity. Islamic dietary practice defined halal and haram foods on the basis of religious texts and practices.
Dietary guidelines of different civilizations
Each civilisation arrived at different dietary guidelines based on their cultural precedents and the resources at hand. In the Middle Kingdom (2,000-1,600BC) of China, the yin and yang were applied to food, which required balancing different types of foods. In Europe, the doctrine of the four humours – based on ancient Greek medicine – was considered in dietary choices to maintain fluid balance in the body.
Early evidence of moderation and balance in diet
Medieval dietary advice centred around the virtues of moderation and balance. While even the most humble of medieval recipes would call for a diversity of ingredients, cookbooks were often structured in ways that reflected the need for a balanced diet. Every meal should include all of the kingdoms of food: grains, meats, vegetables and fruits. And yet cookbooks reveal that access to foods and spices was far from equal, as it depended largely on social status and place.
Dietary Guidelines during the Enlightenment
Influence of scientific discoveries on dietary practices
With scientific discoveries including the germ theory of disease, there were new ways to interpret the causes of death and disease and why food might be linked to them. The Enlightenment, moving from the old to new, scientific ways of thinking, was more than just an intellectual shift. It was also an ethical one; the scientific method, used in the study of diet, required the rejection of alchemy, astrology and other occult sciences.
Emergence of nutritional science
Nutritional science emerged during the Enlightenment, with scientists such as Antoine Lavoisier and Carl von Voit uncovering the world of human metabolism and energy needs. The modern science of nutrition, which informs dietary guidelines, has its roots in these studies.
Relationship between disease and diet
However, the Enlightenment also saw an increasing appreciation that diet was important for disease, and that certain nutrients were implicated in both its prevention and therapy. For instance, James Lind’s experiments on mariners to find a cure for scurvy, demonstrating the essential role of vitamin C prevention, stimulated the search for a better understanding of how diet affected health.
The Birth of Modern Dietary Guidelines
Discovery of vitamins and their roles
In the early 20th century, the discovery of vitamins – named after ‘vital amines’ – explained more about nutrition. Frederick Hopkins and Casimir Funk, among others, determined which nutrients were essential, how they prevented deficiency, and these discoveries led to the fortification of foods and dietary recommendations to ensure vitamin and mineral adequacy.
Dietary guidelines during war times
It was, in fact, the expectation of food shortages and rationing during the two World Wars that first codified dietary advice, with public health campaigns urging people to eat certain foods to meet their nutritional requirements. In the Second World War, citizens in countries as diverse as Britain, Sweden and the US were encouraged to grow their own vegetables. At the time, rationing meant that the term ‘war on food’ carried a literal meaning. In 1942, the US government asked people to ‘ eat your way [into] victory’.
The importance of balanced diet
Contemporary nutrition recommendations are unequivocal in stressing the need to eat a balanced diet. It is believed that this concept evolved over time from the experience of civilisations that observed that it was necessary to include a variety of foods in the daily meals. A balanced diet should include the right proportions of macronutrients (carbohydrates, protein and fats), as well as micronutrients (vitamins and minerals) and fibre. This should be personalised, taking into account age, gender and activity levels.
The Post-War Dietary Guidelines
Changes in dietary habits post-war
The mean dietary consumption of several population groups has changed, since the post-war period, particularly due to the industrialisation of food-related activity, to the increase in overall food availability, and particularly to the changes in the lifestyle of a great part of the population, which has led to a progressive substitution of natural foods for processed foods destined for consumption in the various moments of the day, characterised by increasingly rapid work routines.
Effect of food availability on guidelines
As food supplies grew, guidelines had to evolve to address problems of overconsumption and rising rates of diet-related disease. Moderation and portion control became watchwords. Guidelines increasingly emphasised the need to limit consumption of highly processed foods and added sugars.
Influence of fast food culture on dietary guidelines
Post-war fast-food culture – with mass-produced, ready-to-eat, calorie-dense, nutrient-lite meals – became symbolic of poor dietary behavior that fed an obesity crisis. To counter this trend, dietary guidelines began to emphasise the importance of eating mindfully, cooking for yourself, and eating well when dining out.
Dietary Guidelines in the 20th Century
Government involvement in dietary guidelines
In the 20th century, national governments began to develop guidelines for diets that helped to promote public health. Organisations such as the United States Department of Agriculture (USDA) and Health Canada developed sets of guidelines for healthy eating based on scientific evidence.
First Food Pyramid and eating for health
First introduced in 1992 by the USDA, the Food Pyramid – a visual map of dietary guidelines – emphasised the concept of having a variety of food groups and the need to reduce fat, sugar, and consume more fruits, vegetables and grains (see image on right).
Criticism and controversies of dietary guidelines
The development and implementation of dietary guidelines has a history of criticism and controversy, mostly leaning on claims that guidelines are overly influenced by industry interests; lack representation of diverse populations; and promote a one-size-fits-all approach. Others claim that dietary recommendations change over time, causing confusion for both the general public and healthcare professionals. As such, ongoing and current research along with critically evaluating dietary guidelines are required.
Major Contributors to Dietary Research
Notable nutrition researchers and their contributions
How many nutrition researchers have really changed the way the world eats? On this question the pickings are slim. Take Ancel Keys, whose study of the Siggile diet in 1961 put the link between diet and heart disease on the map. Or Linus Pauling, who decades earlier had studied the micronutrient vitamin C and its role in protecting against scurvy. Or (more recently) Marion Nestle for her work on food politics; Walter Willett for his research into dairy products and sugars; and David Jenkins for his studies on the glycemic index (GI).
Impact of research on dietary guidelines
Scientific research forms the foundation of dietary guidelines. Evidence is needed to support nutrition, epidemiology and metabolic health research – all of which underpin the development of dietary guidelines. This involves studies on dietary patterns and chronic disease; nutrient requirements according to life-stages and health status; individual dietary components and their effects on health; for example, saturated fatty acids and heart disease, fibre and colorectal cancer, and calcium and bone health. Research should constantly update and refine dietary guidelines to allow future considerations and improvements.
Influence of industry on nutritional research
Questions have been raised about the influence of industry on nutrition research and consequently dietary guidelines. Some studies found evidence that industry funding biases research findings and recommendations. Awareness of industry conflicts of interest and promotion of independent research will help to establish dietary guidelines on scientific evidence, rather than on the profit-making motives of food companies.
Dietary Guidelines for the 21st Century
Current understanding of nutrition
Nutrition science has undergone a transformation in the 21st century, evolving from a focus on nutrient adequacy to embrace food and the larger context of environmental sustainability and planetary health. What constitutes a healthy diet is now seen through a new lens that extends the concept of individual human health to consider the health and wellbeing of the entire planet.
Modern dietary guidelines from around the world
The diversity of cultures and traditions, health priorities, and disease profiles found in 21st-century world implies that properly formulated dietary guidelines must also be diverse. In fact, while there is overall consistency in the core recommendations across countries, there is also variation in the prioritisation of one dietary pattern over another and the specificity of guidelines. For instance, some countries might be concerned about the environmental implication of consuming a large amount of meat and prioritise reducing meat consumption. Others might be more worried about obesity and chronic diseases, emphasising the need to reduce intake of added sugars.
Shift towards personalized dietary recommendations
The rise of personalised nutrition has heralded a new era in dietary recommendations. Advances in genomics, the science of the gut microbiome, and wearable technology can help to identify subtle differences between individuals, leading to more tailored dietary recommendations. These dietary guidelines, tailored to our own specific genotype, microbiota composition and lifestyle, should optimise health and disease outcomes.
Influence of plant-based and vegan diets
This is particularly true today, as more and more people become aware of the health and environmental advantages in reducing the consumption of meat and adopting plant-based/vegan diets. Recently, the nutritional guidelines of some countries have recommended more plant-based diets that favour whole grains, legumes, fruits, vegetables, nuts and seeds, and relatively little animal products.
Future of Dietary Guidelines
Potential trends in dietary advice
To finish, what might our dietary guidelines of the future look like, given these trends? As interest in sustainable food systems intensifies, we might expect guidelines to shift further in favour of plant-based eating, with added points for reducing food waste and supporting local, seasonal produce. Likewise, as mindful eating and the benefits of using food for a holistic view of health gain traction, we might see a stronger focus on this way of thinking.
Role of technology in shaping dietary guidelines
Technological progress alone can be very influential in the evolution of the dietary recommendations of the future. Digital health platforms, wearable devices, mobile applications, and other technologies can be used to monitor diet in real-time and provide personalised recommendations. Artificial intelligence and machine learning algorithms could be leveraged to further customise advice and make it more efficient. What technology can do to change the course of dietary guidance remains to be seen. That’s because while technological solutions are relatively easy to develop and implement, they must also be assessed for accuracy and reliability.
Genomics and personalized nutrition
Genomics research has a major role to play in the development of personalised nutrition strategies. By identifying genetic variations that influence the way different individuals absorb and utilise nutrients, genetic information could be used to decode optimal diets for each individual. The application of genomics to dietary guidelines could transform the way we deliver nutrition advice by tailoring it to the specific needs of every individual.
Analysis and Criticism of Dietary Guidelines
Debate over ‘one-size-fits-all’ guidelines
A key criticism of dietary guidelines is that they are often’ one‑size-fits-all’, with it being argued that there are differences regarding individual dietary needs (for example, due to genetics, metabolism or existing health conditions). Critics believe that guidelines need to provide more flexibility, by accommodating individual circumstances and tastes.
Lack of representation in dietary guidelines
Other criticisms raised include a lack of representation, for example, concerning diversity of cultures and socioeconomics, such that dietary guidelines might not consider dietary habits and nutritional challenges within a certain population, leading to health disparities. Making an effort to include diverse representations and to incorporate cultural competence can help to address these concerns.
The industry influence and conflict of interest in dietary advice
Can private industry compromise the integrity of dietary advice? That’s still a live issue, especially if you believe that industry has too much influence over the dietary guidelines. Critics say industry interests often bias nutrition advice to promote specific products, if not whole groups of foods, that fill industry coffers. Transparency about conflicts of interest, and independent review of research studies, are two important consumer protections to help keep dietary guidelines honest. That, and constant scrutiny.
Throughout their history, dietary guidelines have adhered to a common objective: to provide evidence-based recommendations on the food choices necessary to promote health and prevent disease. From ancient wisdom to current scientific knowledge, a basic understanding of dietary guidelines can empower you to make smart decisions about your diet.
