Relationship of dietary regimens to success, efficiency, and cost of weight loss.

One hundred twenty-five subjects in a behaviorally oriented, weight loss program that used several dietary patterns were retrospectively grouped according to the percentage of time they followed one of four dietary regimens: (a) Group 1--partial fasting, 400 kcal; (b) group 2--600 kcal; (c) group 3--1,200 to 1,500 kcal; and (d) group 4--failure to diet. The groups were described and compared regarding program completion, i.e., success and cost of weight loss. Groups 1 and 2 did significantly better than the other two in nearly all respects. Group 1 did better than Group 2 on program completion; the reverse was true when success of those completing 75 and 100 per cent of the program was compared. Groups 1 and 2 did not differ significantly on success variables.