Water and electrolyte exchanges of obese patients on a reducing regimen.

Fat people who attempt to reduce their weight by dieting are often successful at first. After a short period of rapid weight loss, progress is usually less well maintained and may slow down or come to a complete stop before the desired new weight is reached. This frequently happens even when the patient has been carefully supervised and has been collaborating conscientiously. The obese normally carry a moiety of body water which they rapidly lose early in the course of treatment by strict dieting (initial dehydration), but thereafter they may increase their relative body water content (secondary water retention) (Strong, Passmore & Ritchie, 1958; Passmore, Strong & Ritchie, 1958). In these papers we gave quantitative assessments of the initial water losses and subsequent water retention by seven obese patients, each of whom was studied for 6 weeks on a strictly controlled and rigorous reducing regimen. In five of these patients, a complete water balance was derived for the whole period. It comprised the total fluid intake, the metabolic water, the urine, the faecal water and the evaporative water loss. In addition, the sodium and potassium contents of the diet and of the urine and faeces were measured. This paper gives the results of these studies.