It is self-evident that the smallest amount of food that will serve to keep the body in a state of high efficiency is physiologically the most economical, and hence the best adapted for the needs of the organism. Any excess over and above what is really needed is not only uneconomical, but may be directly injurious. This is especially true of the proteid or albuminous foods. It is, however, quite proper to question whether a brief experiment of a few days in which nitrogenous equilibrium is perhaps established at the low level of 4 to 5 grams of nitrogen, the equivalent of 25 to 35 grams of proteid, is to be accepted as fixing the daily requirements of the healthy man, offsetting the customs or habits of a lifetime. Voit himself, however, has clearly emphasized the general principle that the smallest amount of proteid, with non-nitrogenous food added, that will suffice to keep the body in a state of continual vigor is the ideal diet. Proteid decomposition products are a constant menace to the well-being of the body; any quantity of proteid or albuminous food beyond the real requirements of the body may prove distinctly injurious. We see the evil effects of uric acid in gout, but there are many other nitrogenous waste products of proteid katabolism, which with excess of proteid food are liable to be unduly conspicuous in the fluids and tissues of the body, and may do more or less damage prior to their excretion through the kidneys. Further, it requires no imagination to understand the constant strain upon the liver and kidneys, to say nothing of possible influence upon the central and peripheral parts of the nervous system, by these nitrogenous waste products which the body ordinarily gets rid of as speedily as possible. They are an ever present evil, but why increase them unnecessarily? This question brings us back to the starting-point. What is the minimal proteid requirement for the healthy man, or rather, how far can we safely and advantageously diminish our proteid intake below the commonly accepted standards?