The following reviews disclose that the Zone Diet may not be suitable for all. The reasons could be obvious ones: The Zone is too scientific to follow or lack of proper proportion while preparing the meals.

Haven't I heard it somewhere, someday? February 3, 2000
Looks like plain old low-calorie diet to me, just wrapped into lots of scientific blah blah. But - as I am just-this-type-of-food person, I like it quite well, even if I don't know whether my fairly good results have something to do with eicosanoids or with the fact that I'm half-hungry all the time. You can try, if you want, but - if you are not neo-Paleolithic man (as am I, by the looks of it), you'll be not only hungry, but also constantly craving something forbidden to eat (as am I - even being basically a caveman). By the way, can someone tell me how much exercise has a full-time mother of two (2,5 and 1 year)? Maybe I should be eating like tri-athlete, not as a very mildly exercising person, and maybe that is the main reason I'm so hungry...

Huge highs and lows February 9, 2000
I started The Zone in August and didn't have much to lose--about 7 pounds. I lost it within a month and was thrilled. However, if I ever deviated SLIGHTLY from the Zone (i.e. a glass of wine without having protein with it) I would instantly gain five pounds. It was very stressful getting on the scale each morning. My weight has NEVER fluctuated this much.

Also, I have gained back all the weight I lost and have been trying for one month to lose it again (being a PERFECT Zone student) and have had no success. I realize that MANY MANY people have had success on this diet and if you had asked me two months ago I would've given it five stars! But I really think the diet messed up my metabolism. Just a warning!