The land grabbed in some of the world’s hungriest countries by foreign goverments and corporations could feed up to 550m people, according to new research. The crops grown on grabbed land are frequently exported, or used to produce biofuel, but the new work shows it could end malnourishment in those countries if used to feed local people.

Since 2000, at least 31m hectares (77m acres) of land has been acquired by overseas investors seeking to secure food supplies or increase production, a process dubbed land grabbing. Almost half has been in Africa, particularly Sudan. But Indonesia and Papua New Guinea have been targets too. Proponents argue the foreign investment can increase yields and provide development and employment, but critics say the grabs often occur without the consent of those on the land and lead to food being exported.

“Crucial to this debate is the knowledge of the magnitude of the phenomenon: how many people could be fed,” said Prof Maria Cristina Rulli from Politecnico di Milano in Italy, one of the research team. It found that, even accounting for the crops diverted to biofuels, the grabbed land could support 300m-550m people if yields were raised to the levels of industrialised western farming. Even without those yield increases, the land could support 190m-370m people, the researchers calculated.

“Policymakers need to be aware that if this food were used to feed the local populations it would be sufficient to abate malnourishment in each of these countries, even without investments aiming [increase] yields,” said Rulli.

“The world already produces enough food for everyone, yet one in eight people go to bed hungry every night, many of whom are the very people who rely for food on land that big agribusinesses are targeting,” said Hannah Stoddart, head of policy for food and climate change at Oxfam. “Stronger land rights are crucial to ensure that affected communities do not lose out.” She said investment in small-scale farming and more sustainable agricultural practices could reduce hunger for the poorest people.

The new analysis, published on Friday in the journal Environmental Research Letters, calculated the potential maximum crop yield from every known land grab deal over 200 hectares from 2000-2013 and then used the crop’s food calories to determine the amount of people it could feed. The analysis also revealed that while 43% of grabbed land is in Africa, it is the more productive land and more nutritious crops in countries like Indonesia, Malaysia and Papua New Guinea that could provide the most food.

The researchers found many large scale land grabs are taking place in regions facing hunger problems and in great need of food aid. For example, land grabs in Sierra Leone from 2007-2012, were used to grow food crops for export, resulting in local people finding it harder to get enough food and work. In Cambodia, land grabs are leading to the conversion of rice fields to sugar cane plantations and the relocation of peasants to less fertile land.

“Our numbers raise some concern because the target countries have high levels of malnourishment,” said Rulli. “The problem is that there is often no policy in place to prevent investors from exporting the crops produced in the acquired land. If the land was previously used for subsistence farming, the situation likely becomes worse.”