Fast-forward a couple of million years

 Fast-forward a couple of million years 

to when the human diet took another major turn with the invention of agriculture. The domestication of grains such as sorghum, barley, wheat, corn, and rice created a plentiful and predictable food supply, allowing farmers’ wives to bear babies in rapid succession—one every 2.5 years instead of one every 3.5 years for hunter-gatherers. A population explosion followed; before long, farmers outnumbered foragers.

Over the past decade anthropologists have struggled to answer key questions about this transition. Was agriculture a clear step forward for human health? Or in leaving behind our hunter-gatherer ways to grow crops and raise livestock, did we give up a healthier diet and stronger bodies in exchange for food security?

When biological anthropologist Clark Spencer Larsen of Ohio State University describes the dawn of agriculture, it’s a grim picture. As the earliest farmers became dependent on crops, their diets became far less nutritionally diverse than hunter-gatherers’ diets. Eating the same domesticated grain every day gave early farmers cavities and periodontal disease rarely found in hunter-gatherers, says Larsen. When farmers began domesticating animals, those cattle, sheep, and goats became sources of milk and meat but also of parasites and new infectious diseases. Farmers suffered from iron deficiency and developmental delays, and they shrank in stature.