Strict vegetarians such as orthodox Hindus present a special problem, because milk and curds are the only animal protein they will eat. To supply them with sufficient protein of animal origin they must drink 500 cc. of skimmed milk per day, though part of this ration can be taken as curds. As far as fruit, vegetables and starch are concerned, their diet is the same as that of non-vegetarians; they cannot be allowed their usual intake of vegetable proteins from leguminous plants such as beans or from wheat or nuts, nor can they have their customary rice. In spite of these severe restrictions, their average loss is about half that of non-vegetarians, presumably owing to the sugar content of the milk.
Source: Pounds and Inches Manuscript