close up of a flock of sheep

Diversity of diet

Back before agriculture was invented, anthropologists suggest that modern humans, Homo sapiens, had a highly varied diet. Not perhaps as individuals who ate what they could get, but in the aggregate.

Before known civilisations, humans had a diversity of diet. Throughout recorded history, people were eating all sorts of foods, from walrus meat to the roots of desert plants but not at the same time. What each human ate depended on what they could catch or gather, depending on where they were.

As agriculture was popping into a few sharp minds in the fertile crescent and parts of China around 12,000 years ago, humanity had extended itself to just about all parts of the globe. Although in most areas, populations were sparse, including North America, where the first modern humans arrived between 6,000–13,000 years ago. 

Even in these early times, humans had an extraordinary ability to adapt to different environments and essentially moved through the world and populated most places. On an evolutionary timeframe, this mass expansion through hunting and gathering was recent and successful.

Hunting was only sometimes with spears and arrows. 

More often than not, freshwater and marine shellfish were a primary source of protein for the diversity of diet. People often camped next to water sources and relied on edible plants of various types in season. The capture of fire and cooking was a boon, as were various techniques to store and preserve food, including fermentation. 

In prehistory, all the estimates have the global population of H. sapiens at less than 10 million individuals. Humans were widely spread, and we were few in any one place. 

But humans achieved what most other organisms fail to do. We adapted to almost every environment on the planet through a flexible diversity of diet, cooking, and general technical agility. 

Food was still a constraint and had to be taken or gathered in whatever way worked. We will never know specifics, but we know that early humans had a wide diversity of diet across the entire species. It is still being determined whether that wide range of diets persisted within groups or indeed with individuals; it’s likely that many groups just ate the same things most of the time. 

Rather than labour through the story of the invention of agriculture and what happened to food up to and through historical time, including food security, let’s skip to today. 

Today’s diet

In mature economies, most people can access a diversity of diet no matter where they live. 

In Western supermarkets, you can purchase foods from around the world in fresh and prepared forms. Most modern cities offer restaurants from all the major global cuisines and many lesser-known ones. Thousands of different products are available, meaning there is no limit to the range of a person’s diet. The raw materials for cooking and preparing dishes are there, as are the celebrity chefs and cookbooks to tell you how to go about it. 

Diversity of diet is an option. In reality, most individuals have a fairly narrow diet. We know what we like, and we choose and stick with that. This means there are people on all sorts of specialist diets. We’ve got people on the Big Mac diet, the nacho diet, the snack food diet, keto, Atkinsons and Uncle Tom Cobly’s, plus many people consuming way more than they need. 

Individually diet can be narrow, but collectively, there is tremendous diversity of diet, not least because people can retain their cultural affiliations to diet irrespective of where they live around the world. The strong connection between food and culture has also increased dietary availability and what humanity eats. 

We began with a very diverse diet and again with a global supply chain and eclectic communities in the aggregate, we have a very diverse diet. 

So nothing to see here.

walrus hauled out on a rock
Photo by Rod Long on Unsplash

Where does the diversity of diet come from? 

The diversity of the human diet before the invention of agriculture was a direct response to the available resources in the environment. 

Humans learnt how to use a wide range of food types in all the habitats they arrived in. And even when it looked extreme, it was still possible to persist and create a culture around a single source, for example, walrus meat. 

The collective diversity of the human diet before agriculture was a response to the diversity of available foods in the environment. 

Modern agriculture, through industrialisation and intensification, delivers the bulk of our calorific content—now 22 trillion kilocalories daily— via a handful of crops (rice, wheat, sugarcane and corn) and the bulk of our protein and nutrient content in a handful of livestock types (cattle, pigs, goats and chicken). 

We have simplified our food sources or the raw ingredients for processed foods. 

Diversity of diet now comes from a handful of primary ingredients processed and mixed into a wide range of different food types. A typical grocery store in the US contains 4,000 items that list corn ingredients on the label.

Suppose you are fortunate enough to have a high-quality Italian patisserie anywhere nearby. In that case, you will put on a few pounds and be delighted at the prospect, but if you look at the delicious array of cakes and sweet delights on display, many of them contain choux pastry and lemon cream of one sort or another. In other words, lemons, sugar and wheat are key ingredients of Italian cuisine in various combinations. 

Limited diversity from a handful of core ingredients has any number of consequences. And the fortunate billions who can shop in a supermarket still see the diversity of diet because there are products of all different shapes and sizes everywhere.

What the modern diet needs is a diversity of raw ingredients. In terms of raw materials and sources, modern diets are bland.

delicious looking cannoli ready to eat as part of a diversity of diet
Photo by Sangria Señorial on Unsplash

What sustainably FED suggests 

Diversity of diet is a great example of how scale influences an outcome. 

Any one individual could have a narrow or varied diet. Still, even the most adventurous gastronome will only eat a fraction of the foods available in an average supermarket or eaten by all local community members. 

Despite the logic of this proportionality, westerners are exposed to a huge variety of foods. Few realise that these foods—tens of thousands of products—are processed and packaged from a narrow range of ingredients.

Modern agricultural systems are monocultures in the fields and relative monocultures across the food system. They are short on a variety of food types, genetic diversity and diversity of sources.

Globally the human food system relies on just a handful of key plants and animals.

We suggest a pause here.

A sustainable diet is hugely complex, so we put it into our triumvirate of food—ecology—diet. Not least because, in the aggregate, our collective diet has narrowed from its pre-agriculture diversity. 

As individuals, a lack of diversity of diet messes with our physiology, psychology and well-being. 

Collectively a narrow diversity of diet will also make a mess.

Hero image from photo by Jonathan Borba on Unsplash


Mark is an ecology nerd who was cursed with an entrepreneurial gene and a big picture view making him a rare beast, uncomfortable in the ivory towers and the disconnected silos of the public service. Despite this he has made it through a 40+ year career as a scientist and for some unknown reason still likes to read scientific papers.

Add comment

Subscribe to our explainer series

* indicates required

Most discussed