World Resources 
economic case is for more specialized farming. I would indeed 
like to see everyone have a lot more animal protein, but you 
have not proved that it is physiologically necessary. I cannot 
debate the Third World Survey which has not yet been pub- 
lished, but it does not prove that we could not manage with 
Pirie’s grass proteins instead of animal protein if we had to. 
I do not say that we should do so, but I would like to know what 
the physiological minimum is. 
In the same way I can hardly debate your point that we need 
a ton of grain equivalent per person per annum because you 
have not produced any evidence for it yet. Ishould have thought 
my meaning was quite clear when I said that any good farmer 
can produce this requirement on 600 square metres, that is to 
say at the rate of 4 tons per hectare, which is the yield of cereal 
farming in the United States or alternatively of land cultivated 
in Japan. Incidentally the Japanese keep their soil in extremely 
good shape without having any livestock at all. I put in no 
allowance for wastage, because I assume that people who are 
really short of food will take care not to waste it. I am, of course, 
well aware of the needs for seed, and also the danger of losses 
in storage for which quantitative values are very difficult to 
place. 
Trowell: Speaking as a clinician who worked in under- 
developed areas of Africa I feel that the figure for the under- 
calories group of 10-15 per cent of the population is fairly 
realistic, but in Africa we see only seasonal under-nutrition and 
very seldom, apart from civil disturbance or warfare, anything 
like the serious calorie shortage which I understand occurs 
chronically in the East. What happens to people who are 
permanently short of calories? Do they go down continuously 
in weight or do they just do less and less work? We still lack 
basic clinical studies on this problem. In Africa, the best studies 
have been carried out in Gambia where there is seasonal under- 
nutrition, particularly towards the end of the dry season and 
beginning of the rainy season. Before the new crops come in, 
body weight drops and activity decreases; then after the harvest, 
the people feed up again and become more active. ‘This type 
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