A Century of Eating: How Our Diets Have Evolved and What It Means for Health Today

This article is part of our Century of Change series, which explores how metabolic health has been shaped by changes in diet, movement, and stress responses over the last hundred years.

Early 20th Century: Calorie Counting and Restriction

In the early 1900s, dietary advice was grounded in basic energy balance. The concept of the calorie had recently been standardized, and calorie counting emerged as a popular tool for weight control. Lulu Hunt Peters' influential book "Diet and Health: With Key to the Calories" popularized the idea that weight loss was simply a matter of consuming fewer calories than one expended.

This era reflected a cultural shift toward personal control over health, with strict calorie counting and fat restriction shaping eating behaviors, particularly among women. It also marked the beginning of a century-long trend toward applying scientific measurements to personal nutrition.

Mid-20th Century: Fad Diets and the Food Pyramid

As the century progressed, fad diets began to capture public imagination. The Grapefruit Diet and the Cabbage Soup Diet promised rapid weight loss through restrictive, often unscientific methods. While these approaches produced short-term results, they were nutritionally unbalanced and unsustainable.

At the same time, governments sought to standardize dietary guidance. In 1943, the USDA introduced the "Basic Seven" food groups, followed later by simplified versions such as the "Four Food Groups" and, eventually, the Food Pyramid. These tools aimed to provide accessible nutritional advice but were shaped as much by agricultural policy as by evolving nutritional science.

Many of these guidelines emphasized grain and dairy consumption while underplaying the role of nutrient-dense whole foods and healthy fats. Over time, this contributed to widespread dietary patterns that did not always align with optimal metabolic health.

Late 20th Century: Convenience Foods and Diet Industry Booms

Postwar industrialization brought rapid expansion of processed and convenience foods. Frozen dinners, canned goods, and packaged snacks promised efficiency for busy families but were often loaded with sodium, preservatives, and refined ingredients. This period saw a sharp departure from traditional whole-food diets toward manufactured products designed for shelf life and speed.

Alongside this came the rise of the low-fat craze, diet pills, and commercial weight-loss programs. The belief that dietary fat was inherently harmful led to the creation of "fat-free" products that were often high in sugar and additives. Simultaneously, pharmaceutical and supplement-based approaches promised effortless results but often lacked meaningful lifestyle support.

These shifts contributed to the modern landscape of metabolic dysfunction, where calorie-dense, nutrient-poor diets and quick-fix solutions overshadowed foundational lifestyle habits. Over time, poor dietary patterns have been strongly associated with the rise of chronic illnesses, as explored in this article on the connection between processed foods and chronic disease.

Turn of the Century: Low-Carb, Superfoods, and Personalization

The late 1990s and early 2000s ushered in the low-carbohydrate movement, led by diets such as Atkins and South Beach. These approaches challenged low-fat orthodoxy and emphasized protein and healthy fats. While they helped some individuals improve blood sugar stability and lose weight, their popularity also gave rise to oversimplified "carb vs. fat" debates.

Around the same time, "superfoods" entered the cultural vocabulary. Ingredients such as berries, leafy greens, seeds, and fatty fish have gained attention for their nutrient density and potential health benefits. This era marked a growing public interest in the relationship between specific nutrients and long-term wellness.

Advances in nutrition science and technology have since paved the way for more personalized approaches to eating. Today, many people focus on dietary patterns that support metabolic flexibility, emphasizing real food nutrition over rigid fad diets.

What It Means for Health Today

A century of changing dietary trends reveals both progress and pitfalls. Scientific understanding has improved dramatically, but food systems and cultural behaviors have often lagged. Modern eating patterns are shaped by abundance, marketing, and convenience, making it easy to stray from foundational principles of nourishment. These factors play a significant role in the development of long-term health issues, as outlined in Understanding Chronic Disease.

Sustainable, health-supportive eating today involves returning to the basics: eating whole foods to nourish the body, supporting metabolic health through balanced macronutrients, and integrating dietary choices with movement, breath, mindset, and smart supplementation. Practical steps such as learning how to grocery shop for real food and exploring simple whole-food recipes can make these choices more accessible and enjoyable. This lifestyle-based approach aligns with the Four Foundations of Wellness and lays the groundwork for resilience and healthy aging.

Related Articles in This Series

• A Century of Movement: How Exercise and Daily Activity Have Transformed
• A Century of Stress: How Our Responses to Pressure Have Evolved

Nourishing the Future: Bringing Food Back to Its Roots

The past hundred years have seen dramatic shifts in how we eat, from calorie counting to convenience foods to personalized nutrition. By understanding these patterns, we can make informed, sustainable choices that strengthen metabolic health and support long-term well-being.

True dietary progress isn't about following the latest trend. It's about integrating timeless nutritional wisdom with modern science - and using food as a foundational pillar for living well.