The Western Diet and Diseases of Civilization: Understanding How Modern Eating Habits Affect Your Health

Table of Contents

• Key Points
• Introduction: What Is the Western Diet?
• The Landmark Australian Aboriginal Study
• Study 1: The Origins and Evolution of the Western Diet
• Study 2: Traditional Non-Western Diets
• Study 3: Diet, Depression, and Anxiety in Women
• Key Findings Across All Studies
• Clinical Implications: What This Means for Patients
• Limitations: What the Research Cannot Prove
• Recommendations: Practical Steps for a Healthier Diet
• Frequently Asked Questions
• Source Information

Key Points

• Dairy, cereal grains, refined sugars, refined vegetable oils, and alcohol make up 72.1% of daily calories in the U.S. diet.
• Diet-related chronic diseases affect 50–65% of Western adults but are rare in hunter-gatherer cultures.
• In a 7-week study of 10 Australian Aborigines, returning to a traditional diet reversed metabolic abnormalities.
• Traditional diets vary widely, but all avoid industrial-era foods; traditional cooking methods improve nutrient availability.
• In Australian women, Western diets were associated with higher rates of depression and anxiety than traditional diets.

Introduction: What Is the Western Diet?

The Western diet is characterized by high quantities of simple carbohydrates, processed foods, and factory-farmed meat. Researchers have linked this way of eating to a host of major chronic diseases, many of which are uniquely common in civilized cultures. Inhabitants of traditional cultures that maintain their time-honored diets tend to be relatively free of these "Western diseases"—and they only develop them after adopting a diet that is more Westernized.

This pattern has been observed repeatedly across the globe. Whether in Australia, Africa, New Zealand, or the South Pacific, indigenous populations who stick to their traditional foods remain largely free of obesity, diabetes, heart disease, and certain cancers. But when these same populations adopt Western eating habits, their disease rates climb sharply.

The connection between diet and chronic disease is not a new idea. However, a growing body of research now shows that these health effects are not just preventable—they can also be reversed by returning to traditional dietary patterns.

The Landmark Australian Aboriginal Study

In his book In Defense of Food, author Michael Pollan describes a remarkable experiment involving a group of overweight and diabetic Australian Aborigines. These individuals had relocated to settlements near the town of Derby, Australia, where they had adopted a Western lifestyle. As a result, they became overweight and developed metabolic syndrome—a cluster of conditions associated with diabetes, obesity, heart disease, high blood pressure, and cancer.

The researchers attributed their health problems to a diet high in refined carbohydrates and a primarily sedentary lifestyle. But what would happen if they returned to their traditional ways?

During a seven-week stay in the bush, the Aborigines had no access to processed foods. They were completely reliant on foods they hunted and gathered themselves. Their diet consisted of traditional foods such as:

• Fish and shellfish
• Birds
• Kangaroo
• Yams
• Figs
• Bush honey

This contrasted starkly with the Western diet they had been eating, which consisted mainly of flour, sugar, rice, carbonated drinks, alcoholic beverages (beer and port), powdered milk, cheap fatty meat, potatoes, onions, and variable amounts of fresh fruits and vegetables—the local version of the Western diet.

After the seven-week experiment, nutrition researcher Kerin O'Dea reported that all subjects had lost weight and experienced significant health improvements. Their triglycerides (a type of fat in the blood) and blood pressure had fallen, and the metabolic abnormalities associated with their diabetes had either improved or resolved completely.

Pollan notes that these diseases of civilization—obesity, diabetes, heart disease, hypertension, and certain diet-related cancers—have long been recognized as products of the typical Western diet. But O'Dea's study was the first to show that these health effects can be reversed by a return to traditional hunter-gatherer diets.

Study 1: The Origins and Evolution of the Western Diet

This 2005 report, published in the American Journal of Clinical Nutrition and headed by Dr. Loren Cordain—Professor of Health and Exercise Science at Colorado State University and author of The Paleo Diet—examines seven crucial dietary changes introduced since the rise of agriculture and animal husbandry. These include:

1. Glycemic load (how quickly foods raise blood sugar)
2. Fatty acid composition
3. Macronutrient consumption
4. Micronutrient density
5. Acid-base balance
6. Sodium-potassium ratio
7. Fiber content

Cordain argues that these changes occurred too recently—approximately 10,000 years ago—for the human genome to adapt, and that they are the cause of many of our diseases of civilization.

What the Researchers Found

Cordain identified five food groups that would not have been available to pre-agricultural humans yet now make up a staggering 72.1% of the total daily calories consumed by all people in the United States:

Combinations of these foods also make up the processed foods—cookies, cake, baked goods, crackers, chips, pizza, soft drinks, candy, and ice cream—that are ubiquitous in the American diet. The modern diet also contains high levels of salt and fatty domestic meats, foods that were not a part of ancestral diets.

Study Methods

The American Journal of Clinical Nutrition report reviewed 172 different articles and studies on ancestral diets, the evolution of the Western diet, and Western diseases, published between 1967 and 2004. Topics ranged from "Diet and nutrition of hunter-gatherers" to "Salt and gastrointestinal cancer."

Key Results

Cordain and his colleagues concluded that the prevalence of these foods in the modern Western diet is directly linked to "diseases of civilization" such as:

• Obesity
• Type 2 diabetes
• Hypertension (high blood pressure)
• Coronary heart disease
• High cholesterol
• Acne
• Polycystic ovary syndrome
• Certain cancers
• Skin conditions

The study states that "diet-related chronic diseases represent the single largest cause of morbidity and mortality." Although these diseases are rare or non-existent in hunter-gatherer cultures and those who maintain traditional diets, they are present in 50–65% of the adult population in Western cultures.

Analysis

The report is remarkably thorough in its analysis of the differences between ancestral diets and the modern Western diet. Notably, the evidence shows that there is no single dietary element that can be labeled as the cause of chronic disease (such as saturated fat). Rather, Western diseases are the product of a combination of dietary elements. Interestingly, no specific ancestral diet is defined or identified as being the ideal diet for all cultures—the key theme is avoiding industrial-era foods.

Study 2: Traditional Non-Western Diets

This report by Elizabeth Lipski, PhD, CCN, was published in Nutrition in Clinical Practice and takes a closer look at the health benefits and characteristics of several traditional diets. Lipski studied cultures including the Tohono O'odham Indians, Eskimos in Labrador, the Maori in New Zealand, Gaelic populations in the Outer Hebrides, and the Hunza in the Himalayas. She notes that "whenever people living traditionally mesh with western culture, noninfectious diseases of modern culture soon follow."

Historical Observations

Lipski's report reviews the diets and health status of various traditional cultures around the world. She cites the work of Albert Schweitzer, Weston Price, and others who studied the dietary habits and health status of indigenous populations in the earlier part of the twentieth century. Physicians living in eastern and central Africa, Australia, New Zealand, the southern Pacific, and other isolated regions saw few or no instances of dental caries (cavities), cancer, heart disease, appendicitis, diverticulitis, diabetes, infectious disease, and other common maladies in the West. Many of these sources reported that the health of native populations degenerated when they were introduced to European diets.

Study Methods

Using 60 different articles and studies, Lipski examined early observations about the health of indigenous populations, contemporary research on indigenous diets, traditional cooking methods, functional foods in traditional diets, and the trend towards increased health when traditional diets are restored.

Key Results

Lipski notes that although traditional diets varied widely, nearly all traditional cultures used cooking methods that "enhance digestion and nutrient availability," such as:

• Soaking
• Fermentation
• Pounding
• Sprouting

Notably, use of these traditional cooking methods decreased when a family's wealth increased. Traditional cultures also employed "folk functional foods" for their medicinal and healing properties.

Lipski cites several studies that observed improvements in health after the return to a traditional diet, including O'Dea's study of the ten Australian Aborigines. A similar study of overweight Hawaiians who returned to a traditional Hawaiian diet for 21 days saw significant improvements in:

• Weight
• Glucose (blood sugar) levels
• Serum triglycerides
• Total cholesterol levels
• Systolic blood pressure

Analysis

Lipski's research supports Pollan's position that traditional diets vary widely in their nutritional composition, yet all are effective at safeguarding against the diseases of modern civilization. However, returning to a traditional diet is not always feasible. As Lipski notes, traditional foods, skills, and practices "are slowly vanishing as the elders die." Although some populations understand the role of traditional foods in preventing or improving disease states, many have lost access to traditional foods or the knowledge and skills to identify or prepare them.

In other cases, traditional foods have become more contaminated with mercury, pesticides, and other pollutants. This is demonstrated by the Arctic Dilemma, where traditional, high-fat foods are less beneficial than they once were due to environmental contaminants. The challenge, then, is to determine how to increase the availability of unpolluted traditional foods in both traditional and modern cultures.

Study 3: Diet, Depression, and Anxiety in Women

Although the typical Western diet is commonly recognized as a factor in health conditions such as obesity, cardiovascular disease, and type 2 diabetes, less scientific evidence exists on the relationship between diet and psychological health. Authors of this study, published in the American Journal of Psychiatry, note that diet affects biological processes that influence psychological health, including:

• Inflammation
• Brain plasticity and function
• The stress response system
• Oxidative processes

Study authors also note that previous studies examining the association between diet and psychological health focused on individual nutrients or food groups, which provide an incomplete picture of the effects of diet on mental health.

Study Methods

Rather than focusing on individual nutrients or food groups, this study examined the effects of habitual diet quality on mental health in more than 1,000 Australian women between the ages of 20 and 92.

Participants, who were randomly selected from the population, completed:

1. A comprehensive food frequency questionnaire
2. The 12-item General Health Questionnaire (GHQ-12)—higher scores indicate more health problems
3. A clinical interview to assess psychological health

Researchers were particularly interested in the high-prevalence mental disorders of major depressive disorder, mild chronic depression, and anxiety disorder.

For the purpose of the study, "traditional" dietary patterns were defined as those high in fruits, vegetables, meat, fish, and whole grains. "Western" diets were those composed mainly of processed or fried foods, refined grains, and sugar.

Key Results

Results were adjusted for age, socioeconomic status, education, and health behaviors. The findings were striking:

• Traditional diets were associated with lower rates of depression and anxiety disorders.
• Better diet quality further decreased the risk of psychological symptoms.
• Western diets were associated with higher GHQ-12 scores (indicating more psychological problems).
• The Western diet was also associated with an increased risk of major depression or mild chronic depression.

Study authors also noted that, due to adjustments for overall caloric intake, the amount of unhealthy food may be more relevant to psychological health than the proportion of unhealthy food in the overall diet.

Analysis

While further research is necessary to prove causation, study authors note that the results are consistent with other research that shows associations between habitual diet quality and medical outcomes, including risk of major chronic diseases such as cardiovascular disease and cancer. Individuals suffering from psychological issues, or those diagnosed with depression or anxiety disorders, would be prudent to increase their intake of fruits and vegetables and decrease their consumption of processed, refined, and sugary foods.

Key Findings Across All Studies

When viewed together, these studies paint a remarkably consistent picture of the relationship between diet and health:

• Five food groups—dairy products, cereal grains, refined sugars, refined vegetable oils, and alcohol—make up 72.1% of the total daily calories consumed in the United States.
• Diet-related chronic diseases are present in 50–65% of the adult population in Western cultures, yet are rare or non-existent in hunter-gatherer cultures.
• Returning to a traditional diet can reverse metabolic abnormalities—as demonstrated by the Australian Aborigines who improved in just 7 weeks and the Hawaiians who improved in just 21 days.
• Traditional cooking methods (soaking, fermenting, pounding, sprouting) enhance digestion and nutrient availability.
• Dietary patterns, not individual nutrients, are associated with both physical and psychological health.
• Western diets are associated with higher rates of major depression and mild chronic depression in women.

Clinical Implications: What This Means for Patients

The health risks associated with the typical Western diet are undeniably extensive and severe. But the research also offers a hopeful message: dietary changes can produce meaningful improvements in a relatively short period of time.

For patients with metabolic syndrome, type 2 diabetes, or cardiovascular risk factors, the evidence suggests that shifting towards a more traditional, whole-food dietary pattern can lower triglycerides, reduce blood pressure, improve glucose control, and reduce cholesterol levels. The Hawaiian study showed measurable improvements in all of these markers in just three weeks.

For patients struggling with depression or anxiety, the findings suggest that diet quality may play an important role in mental health. The Australian women's study found that better diet quality was associated with lower rates of depression and anxiety disorders, even after accounting for socioeconomic status, education, and health behaviors. While diet should never replace professional mental health treatment, improving dietary patterns may be a valuable complement to therapy and medication.

However, a transition to a more traditional, plant-based diet is problematic for many people due to higher costs, limited access to unprocessed foods, or food insecurity. In addition, problems such as the Arctic Dilemma—where traditional foods are increasingly contaminated with environmental pollutants—compound the difficulty of sourcing healthy, whole foods. These barriers need to be acknowledged and addressed at both individual and policy levels.

Limitations: What the Research Cannot Prove

It is important to understand what these studies can and cannot tell us. The research reviewed here is largely observational, meaning it shows associations between diet and health outcomes but does not prove that diet causes those outcomes.

For example, although traditional diets are associated with better psychological health in the Australian women's study, the association does not prove causation. The authors themselves recommend further studies to rule out reverse causality (where mental health problems lead to poorer dietary choices, rather than the other way around) and confounding (where other factors, such as income or lifestyle, explain the relationship between diet and health).

Additionally, small studies—such as the seven-week Aboriginal study with only ten participants—are compelling but limited in scope. Larger, longer-term randomized controlled trials would provide stronger evidence.

Finally, the reality of modern food systems means that returning to ancestral diets is not always practical, affordable, or even safe in cases where traditional foods are contaminated with environmental pollutants.

Recommendations: Practical Steps for a Healthier Diet

Adopting a set of "food rules" such as those outlined in Michael Pollan's In Defense of Food can assist with the transition to a healthier diet. Here are evidence-informed suggestions based on the research reviewed:

1. Avoid processed foods as much as possible. Choose foods with few or no ingredients. The research consistently shows that processed foods—combinations of refined grains, refined sugars, refined vegetable oils, and additives—are at the heart of the Western diet problem.
2. Focus on whole fruits and vegetables. The women's mental health study found that diets high in fruits, vegetables, meat, fish, and whole grains were associated with lower rates of depression and anxiety.
3. Keep the diet simple and choose quality over quantity. As Pollan puts it: "Eat food. Not too much. Mostly plants."
4. Buy whole grains in bulk and buy produce in season to keep food costs down.
5. If organic produce is not affordable, conventional produce is still preferable to refined, processed foods. You can reduce your exposure to chemicals and pesticides by choosing produce with the lowest pesticide residues, such as asparagus, sweet peas, mangoes, and cantaloupe, according to the Environmental Working Group.
6. Be cautious about dietary fads and "new" scientific research regarding specific nutrients or food groups. As Pollan illustrates, emerging research—especially that which relates to specific nutrients—often creates more confusion surrounding healthy food choices and can in fact lead to more health problems.

Education is also critical. A Consumer Reports Health poll from early 2011 found that 9 in 10 Americans say their diet is healthy, but only a quarter limit the amount of fat and sugar in their diet, and only one-third of participants reported eating five or more servings of fruits and vegetables daily. This discrepancy reveals a lack of understanding about what constitutes a healthy diet, which puts people at risk of major chronic disease and psychological problems.

The overall message from the research is clear: the Western diet is a major contributor to the chronic diseases that plague modern society. But the flip side is that diet can also be a powerful tool for prevention and healing. By moving towards traditional, whole-food eating patterns—even incrementally—patients can take meaningful steps towards better physical and mental health.

Frequently Asked Questions

What is the Western diet and why is it linked to chronic disease?

The Western diet is high in refined sugars, processed foods, and factory-farmed meat. Research links it to obesity, type 2 diabetes, heart disease, and depression. Traditional, whole-food diets are associated with lower rates of these diseases, suggesting that overall diet quality, not just calories, plays a central role in health.

Can changing my diet reverse diabetes or metabolic syndrome?

In a seven-week study, ten overweight diabetic Australian Aborigines who returned to a traditional hunter-gatherer diet all lost weight. Their triglycerides, blood pressure, and diabetes-related abnormalities improved or resolved completely. Another study of overweight Hawaiians on a traditional diet for 21 days showed improvements in weight, glucose, cholesterol, and blood pressure.

How quickly can dietary improvements affect health?

The Australian Aboriginal study showed significant metabolic improvements in just seven weeks. The Hawaiian study found measurable improvements in weight, blood sugar, blood fats, and blood pressure within 21 days. These results suggest that meaningful health changes can occur within a few weeks of returning to a whole-food, traditional eating pattern.

Does diet affect depression and anxiety?

A study of over 1,000 Australian women found that traditional diets rich in fruits, vegetables, meat, fish, and whole grains were associated with lower rates of depression and anxiety. Western diets high in processed and sugary foods were linked to higher rates. This is an association, not proven cause, but improving diet may complement mental health care.

What foods should I focus on for a healthier diet?

Focus on whole fruits, vegetables, whole grains, meat, and fish. Avoid processed foods made from refined grains, sugars, and vegetable oils. Choose foods with few or no ingredients. Traditional cooking methods like soaking, fermenting, pounding, and sprouting can enhance nutrient availability and digestion.

What makes it hard to eat a traditional diet today?

Barriers include higher costs, limited access to unprocessed foods, and food insecurity. Traditional foods may also be contaminated with environmental pollutants, as seen in the Arctic Dilemma. These challenges require individual and policy-level efforts to increase availability of unpolluted whole foods.

Is the evidence linking diet to disease conclusive?

Most research is observational, showing associations rather than proof of cause. Some studies are small, like the seven-week Aboriginal study with ten participants. Larger, long-term randomized controlled trials would provide stronger evidence. For now, moving toward whole-food eating patterns appears beneficial but is not a substitute for professional medical advice.

Should I get a second opinion about using a traditional whole-food diet to treat my metabolic syndrome or type 2 diabetes instead of just taking medication?

A patient with type 2 diabetes, metabolic syndrome, or cardiovascular risk factors may benefit from a second opinion when their current treatment plan relies only on medication and does not address dietary patterns. Returning to a traditional whole-food diet can lower triglycerides, blood pressure, glucose, and cholesterol within weeks, as seen in studies of Australian Aborigines and Hawaiians. However, these findings are observational and small, so a second opinion can help review whether dietary changes are a safe complement to therapy and how to overcome practical barriers like food access and contamination. Diagnostic Detectives Network provides independent expert second opinions.

Source Information

Original article title: The Western Diet and Diseases of Civilization

Author: Karen Eisenbraun

Published: November 13, 2011, for Nat 309: Topics in Holistic Nutrition

Primary studies referenced:

• Cordain, Loren et al. "Origins and evolution of the Western diet: health implications for the 21st century." The American Journal of Clinical Nutrition. http://www.ajcn.org/content/81/2/341.long
• Jacka, Felice et al. "Association of Western and Traditional Diets with Depression and Anxiety in Women." American Journal of Psychiatry. http://ajp.psychiatryonline.org/cgi/content/full/167/3/305
• Lipski, Elizabeth. "Traditional Non-Western Diets." Nutrition in Clinical Practice. http://ncp.sagepub.com/content/25/6/585.full.pdf+html
• Pollan, Michael. In Defense of Food (2008).
• Mann, Denise. "Americans Say Their Diet is Healthy, but Is It?" WebMD Health News (2011).
• Environmental Working Group: Shopper's Guide to Pesticides in Produce. http://www.ewg.org/foodnews/summary/

This patient-friendly article is based on peer-reviewed research and is intended for educational purposes. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or another qualified health provider with any questions you may have regarding a medical condition or dietary changes.