This study examines the effects of a low-calorie raw juice diet on the level of serum ferritin in adults and analyzes nutrient intake from the diet. There were significant differences between juices; the highest calorie was provided by pear juice, highest crude protein, vitamin A, and vitamin B2 levels were from green Juice 1; and highest vitamin C and vitamin B1 levels were from fruit juices. The ratio of estimated energy requirements (EER) for the participants was 56.2% from the raw juice diet. The percentages of recommended intake (RI) from the raw juice diet of protein (57.9%), dietary fiber (19.1%), niacin (6.2%), calcium (0.1%), and magnesium (0.2%) were lower than 75%. However, those of RI of vitamin A, vitamin B1, vitamin B2, vitamin B6, and vitamin C were 1796.5%, 7481.7%, 1915.5%, 30858.7%, and 7500%, respectively, exceeding the tolerable upper intake level (UL) for vitamin A, vitamin B6, and vitamin C. There were significant decreases in weight, the body mass index (BMI), body fat mass, and skeletal muscle mass in males and females. After the diet program, serum iron and SOD (superoxide dismutase) showed significant decreases, whereas RBC, hemoglobin, hematocrit, and serum ferritin showed significant increases. There were negative correlations between serum ferritin and weight and between serum ferritin and skeletal muscle mass for all participants. There were negative correlations between serum ferritin and skeletal muscle mass for males and between serum ferritin and body fat mass for females. These results suggest that a raw juice diet can supplement a regular diet to prevent excess or deficient nutrient intake.