This grapefruit diet plan is Bad Psychology because it fails to address the problem of your fat body image. Unless you follow the ideas suggested here, any weight loss program you start such as is likely doomed from the start.
The grapefruit diet is Bad Psychology because it will almost surely result in ultimate failure with subsequent loss of wellbeing. This grapefruit diet surely will ultimately fail because it does not require some regular mild aerobic exercise so that your metabolism can change.
This grapefruit diet is Bad Nutrition. No one should try this rigidly for more than a few days at a time. A better choice would be just to add cabbage soup/ grapefruit/ other-healthier-food to your current diet. Doing things by ADDING will help you in Changing Food Preferences.
There are some grapefruit diets which just add grapefruit to a relatively healthy diet because grapefruit supposedly has some fat-burning enzyme. Don't we wish!
Please look below for the Brainwashing programs which do have the ingredients for success.