The effects were studied in 8 women of the consumption of the low carbohydrate diet, in which the amount of carbohydrate was restricted to some 80 g a day, but protein and fat were allowed freely. As in previous studies, the energy intake was found to be about 30 % lower on this diet than on the subject’s habitual diet, but the nutrient content was not reduced. During the 6 weeks of the dietary period, there was no change in the plasma concentration of triglyceride, cholesterol or uric acid. There was an intermittent urinary excretion of small amounts of ketone bodies, consistent with the degree of ketosis accompanying moderate weight loss. The urinary excretion of nitrogen and creatinine were unchanged, indicating no significant loss of tissue protein.