Fig. 2.

The inclusion of food waste in pig diets linearly reduces the land required per kg of pork live weight; r = 0.97, n = 78, p < 0.0001. This linear relationship reflects that the inclusion of food waste in pig feed (a) has no effect on the feed conversion efficiency (it substitutes conventional feed almost 1:1 on a dry matter basis (t = 1.15, p = 0.26)), and (b) does not have a large effect on growth rates (for more details see Appendix D). Some diets have a land use of zero, without being 100% swill: they contain a small amount of other ingredients, such as vitamins and minerals, which also do not require agricultural land.