this person is you, and you ll probably lose like 15 lbs if you do it for 3 months. you would lose more, if you had more to lose, but you dont
sounds like an eating disorder waiting to happen and as a recovering anorexic I would not wish this hell on anyone!She is fine the way she is and if you notice her starting to do this type of thing RAT HER OUT eating healthy and exercise are one thing this is another a person has to have at least 1200 cals a day to function!
It sounds like a crash diet and she likely to end up being malnourished. Water to begin with is not really a nutrient while fruit and veg are not particularly nutritious. That leaves the dinner which she may have instead of salad, it really depends what kind of dinner this is but it s not likely to be enough. She would be doing well to use some nutritional supplements on top of food.
For her height, she really doesn t need to lose any weight. This plan isn t unhealthy in general, but for her she shouldn t do it all the time. Tell her to maybe do that during the week, but Friday-Sunday, she should binge, which means eating the things she likes and being inactive. This will still help her lose whatever shes wanting to, but slowly, which is the healthy way.