According to Cornell University scientists: "The heavy dependence on fossil energy suggests that the US food system, whether meat-based or plant-based, is not sustainable". However, they also write: "The meat-based food system requires more energy, land, and water resources than the lactoovovegetarian diet. In this limited sense, the lactoovovegetarian diet is more sustainable than the average American meat-based diet." One of these Cornell scientists has advised that the US could feed 800 million people with grain that livestock eat. He "depicted grain-fed livestock farming as a costly and nonsustainable way to produce animal protein", but "distinguished grain-fed meat production from pasture-raised livestock, calling cattle-grazing a more reasonable use of marginal land".