Average UK male: 80kg
Average UK female: 65kg
Male:female ratio: 1:1
Ergo approximate 14 patients per ton. Ish. Chop of a couple of limbs, and you'll be back to the exact ton.
Unfortunately, if you want your Soylent Green to be less fatty, we'd need to mix in some low BF Europeans to add some extra texture and improve the protein balance.