JAMA 100 Years Ago Section Editor: Jennifer Reiling, Assistant Editor.
It has been a common assumption that very rapid losses of body weight are due to largely increased loss of water from the body. The marked weight changes which occur within a few minutes during a boat race by a college crew afford a case in point. Perspiration is excessive as the result of the attempt of the body to get rid of its surplus heat; and it has usually been believed that the greater part of decline in weight is directly attributable to the water output.
It is, of course, not unbelievable that material losses of stored tissue material may explain decided changes in body weight under certain conditions, As a matter of fact it has been difficult to make any sweeping statements as to the causes involved—as to whether such losses primarily involve water or metabolized tissue—because of the paucity of data on the water balance of the body. Few experimental researches furnish the data which will enable one to deduce the daily intake of water aside from that entering the body in the form of fluids; yet in view of the fact that most of our common food materials, such as meats, fruits, vegetables, etc., contain a large abundance of water, amounting usually to more than half and sometimes as high as 90 per cent. of the products ingested, obviously water enters the organism in varied association with the true nutrients. This content of water needs to be known before one can learn the whole story of the income und outgo. In addition to all this, water is formed by the oxidative reaction of metabolism; but this particular contribution is not readily ascertainable.
THE CAUSES OF SOME RAPID CHANGES IN BODY WEIGHT. JAMA. 2012;308(11):1074. doi:10.1001/jama.2012.3210