For years we've been told that traditional foods are unhealthy because of their saturated fat content. In place of grass-fed meat, grass-fed dairy products, and eggs from hens running on pasture, we now mostly eat grain-fed meat and processed factory foods – and we've witnessed an epidemic of disease, from type-2 diabetes to heart disease and cancer. Modern agriculture has locked us into an unhealthy, vicious circle, with degraded foods pouring from an overstretched, impoverished landscape. There's a simple remedy: the grass-fed movement. We can make sure that the meat, dairy foods and eggs we buy come from animals grazing on or running in pasture, as they always used to. This will also put life back into our soils and wildlife back onto our farmland. Graham Harvey, agricultural advisor to BBC Radio 4's The Archers, lays out all the arguments for grass-fed food – why it's good for us, and why it's good for the planet.