Replacing half of the meat eaten worldwide with crickets and meal-worms would cut farmland use by a third, reducing emissions of greenhouse gases, researchers said.
"A mix of small changes in consumer behaviour, such as replacing beef with chicken, reducing food waste and potentially introducing insects more commonly into diets, would help achieve land savings and a more sustainable food system," said Peter Alexander, from University of Edinburgh in the UK.
While consumers' reluctance to eat insects may limit their consumption, even a small increase would bring benefits, researchers said.
Using data collected primarily by the UN's Food and Agriculture Organisation, scientists compared the environmental impacts of conventional meat production with those of alternative sources of food.
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Researchers at Edinburgh and Scotland's Rural College considered a scenario in which half of the current mix of animal products is replaced by insects, lab-grown meat or imitation meat.
They found that insects and imitation meat - such as soybean-based foods like tofu - are the most sustainable as they require the least land and energy to produce. Beef is by far the least sustainable.
The team said halving global consumption of animal products by eating more insects or imitation meat would free up 1,680 million hectares of land - 70 times the size of the UK.
Similar land savings could also be made by switching from the current mix of animal products to diets higher in chicken and eggs, the team said.
They found that the land required to produce these was only marginally greater than for insects and imitation meat.
Globally, pasture covers twice the area of cropland, and livestock consume around a third of all harvested crops, they said.
The research was published in the journal Global Food Security.