Nitrogen balance studies during modified fasting.

Protein or nitrogen depletion may be harmful and deleterious as reports of deaths in obese patients fed by liquid protein diets have shown. The aim of our studies was to determine the protein losses (by urinary nitrogen losses) during treatment of obesity with modified fasting over four weeks under inpatient conditions. Sixty-one patients were treated in our metabolic ward with modified fasting randomized into four groups. The daily diet consisted of 33-50 g protein/day, 1-10 g fat/day and 25-45 g carbohydrates/day thus providing 240 to 450 kcal/day or 1.0 to 1.9 MJ. The mean weight losses ranged between 11.0 +/- 0.7 kg and 13.9 +/- 0.9 kg in 28 days. The acceptability and compliance of the four applied diets were excellent and no severe side effects could be observed. The nitrogen balances could be equilibrated from the third week on. The composition of weight lost during modified fasting was as follows. The percentage of body protein ranged between 3% and 16% and the percentage of adipose tissue between 63% and 79% of the total weight loss. Therefore modified fasting represents a very effective and safe therapy of massive obesity.