By changing how existing cropland is used around the world, enough food to feed 4 billion more people could be produced, according to new research from the Institute on the Environment at the University of Minnesota.

The researchers contend that reallocating croplands away from fuels and animal feed could boost the food available for people by 70 percent without clearing more land.

Beneficial effects of cropland shift could be seen at a variety of levels across the globe, the researchers report. Cattle raised for their beef, for instance, demands huge amounts of cropland for their feed, which is often corn. If cropland was used to feed fewer cows and more chickens or pigs, the researchers report it would increase the agricultural efficiency of the land to provide enough food for millions of people.

The study sought to quantify the net benefits to food security that would arise if all existing cropland was used to produce food for people, rather than food for animals or material for fuels.

"We essentially have uncovered an astoundingly abundant supply of food for a hungry world, hidden in plain sight in the farmlands we already cultivate," said graduate research assistant Emily Cassidy, lead author of the paper published in Environmental Research Letters.

"Depending on the extent to which farmers and consumers are willing to change current practices, existing croplands could feed millions or even billions more people," Cassidy said.

As world population continues to increase and the number of newly-affluent, meat-hungry people also grows, demand for crops is expected to double by 2050, the researchers report.

Meat production takes a huge toll on food security because it take as many as 30 crop calories to produce a single calorie of meat, the study reports, also adding that the increased use of land to produce crops for biofuels is also taking away from food-production possibilities.

The study looks at agricultural data and the allocation of crop calories from India, China, Brazil and the US.

They found that while India allocates 90 percent of calories to feeding people, the other three allocate 58 percent, 45 percent, and 27 percent, respectively.

It should be noted that India, the country with the most efficient allocation of crops for human consumption, also has the highest number of vegetarians or people that no not eat certain kinds of meat.

"Noting the major cultural and economic dimensions involved, the researchers acknowledged that while a complete shift from animal to plant-based diets may not be feasible, even a partial shift would benefit food security," the researchers said in a statement. "Quantifying the impact of various strategies, they found that a shift from crop-intensive beef to pork and chicken could feed an additional 357 million people, and a shift to non-meat diets that include eggs and milk could feed an additional 815 million people."

Cassidy and colleagues mapped the extent and productivity of 41 major crops between 1997 and 2003, adjusting numbers for imports and exports and calculating conversion efficiencies of animal feed using US Department of Agriculture data. The researchers assumed humans need an average of 2,700 calories per day, and grazing lands and animals were not included in the study. Among the team's findings:

  • Only 12 percent of crop calories used for animal feed end up as calories consumed by humans.
  • Only 55 percent of crop calories worldwide directly nourish people.
  • Growing food exclusively for direct human consumption could boost available food calories up to 70 percent
  • U.S. agriculture alone could feed an additional 1 billion people by shifting crop calories to direct human consumption.
  • When calculated on the basis of protein rather than calories, results were similar. For instance, of all plant protein produced, 49 percent ends up in human diets.