The 17 Day Diet: Try It for 17 Days — It May Work

Losing a dress size in little over two weeks may sound too good to be true. That is exactly what Dr. Mike Moreno, a family practitioner in San Diego, promised in his bestselling 2011 book The 17 Day Diet: weight loss of 10 to 12 pounds in the first cycle, with results he insisted would be sustainable.

The plan is organized into four 17-day cycles. Dieters vary their intake of carbohydrates, proteins, and fruits between cycles — the idea being to keep the body's metabolism from settling into the "habit" of a steady routine, which tends to slow weight loss over time. The first cycles cut sugars and processed foods, eliminate alcohol, and emphasize what Moreno calls "clean" eating: breakfast every morning, more water, and unprocessed, natural foods.

Moreno told Good Morning America that he chose 17-day periods because it is "right before the time when the body starts to recognize the diet as a habit and metabolism starts to slow as a result."

The honest caveats: most of that dramatic early loss is water weight, not fat. Rapid-loss cycles are notoriously hard to sustain, and the evidence for "confusing the metabolism" with rotating menus is thin. What is real in Moreno's program is the part that has nothing to do with the number 17 — eating unprocessed food, cutting sugar and alcohol, eating breakfast, drinking water. Those are the durable parts, and they do not require a book.

This article is general health information, not medical advice. Anyone considering a weight-loss program should consult a qualified health professional first.