Cooked leafy vegetables make a substantial proportion of our food today but if we look at their origin, leafy greens were first dished up some 3,500 years ago in west Africa, archaeologists and archaeo-botanists have unearthed.

The teams from Germany`s Goethe University and University of Bristol in the UK examined more than 450 pre-historic pots and 66 of them contained traces of lipids, that is, substances insoluble in water.