The plan specifies a very specific diet which is supposed to be followed exactly. Artificial sweeteners are used in place of sugar. The diet is to be followed for 7 or 14 days, alternating with a less rigorous regime.
Critics acknowledge that the diet gives quick results, but say that weight loss on the Scarsdale diet results simply from the reduced caloric intake; is mostly water; is quickly regained; and that the diet is so extreme as to be unhealthy.