This study investigated the acceptability of two very-low-calorie diets in 16 moderately overweight persons participating in a weight reduction program. Subjects were prescribed a 1000-1200 kcal balanced diet the first month and asked to complete appetite and mood scales on a weekly basis. They were then randomly assigned to either a protein-sparing-modified fast (PSMF) or a protein-formula-liquid diet, each of which provided about 400 kcal daily. Analysis of the appetite data showed that PSMF subjects reported significantly less hunger and preoccupation with eating than did liquid diet subjects during 2 of the 4 weeks on a very-low-calorie diet. Subjects in both conditions reported significant reductions in anxiety. Results are discussed in terms of possible advantages of PSMF.