Dietary changes in the US could feed significantly more people from existing agricultural land, suggests a new study that takes into account the per-person land requirements of different diets.Using 10 different scenarios ranging from the average American diet to a purely vegan one, a team led by scientists from the Tufts University estimated that agricultural land in the contiguous US could have the capacity to feed up to 800 million people -- twice what can be supported based on current average diets.The new "food-print" model, published recently in the journal Elementa, shows that a vegetarian diet that includes dairy products could feed the most people from the area of land available."Our approach challenges the 20th century emphasis on increasing yield and production. Improving crop yields remains vitally important, but it is not the only way to increase the number of people fed per acre. Our aim is to identify potential agricultural-sustainability strategies by addressing both food consumption and production," said lead author Christian Peters.
The researchers found that a lacto-vegetarian diet (a vegetarian diet that includes dairy products) had the highest carrying capacity, meaning that it could feed the most people from the area of land available.Diets including some meat can feed more people than vegan diets, depending on estimates of how much land is suitable for crop cultivation, while the baseline diet had the lowest carrying capacity and required eight times more land than a vegan diet.As the amount of meat in the diet was reduced between scenarios, the amount of land necessary for crops to feed livestock was also reduced."In our study, the estimates of carrying capacity for each diet are sensitive to assumptions about the area available for cultivated cropping. Furthermore, since most diet scenarios were consistent with the Dietary Guidelines for Americans, differences in carrying capacity should represent the trade-offs for food preferences rather than nutritional quality," Peters said.