The Grapefruit diet is a popular weight loss mechanism, in part because it has 2 basic approaches. The first is obvious. You only eat grapefruit halves for an extended period of time along with grapefruit juice should you choose. I don’t feel like I really need to say it. But if you are only eating grapefruit, you will lose weight.
The second manner is actually a bit different. You still eat meals, you eat reasonable meals. But you include either ½ a grapefruit or 1 8oz glass of grapefruit juice in every single meal of your day. This is obviously more reasonable. But you aren’t actually guaranteed to lose weight, in fact many do not lose weight when using this form of the grapefruit diet.

So does it work out at all? Well you can either go to the extreme of a diet you can’t sustain, meaning you will gain all the weight back, or you can use a diet with which you probably won’t actually lose weight in the first place. So realistically speaking, you shouldn’t use the grapefruit diet in either form. Either way, you would just be wasting more time and money than is really necessary, even though you aren’t technically paying extra money beyond the cost of the grapefruit itself. It’s still ultimately speaking a greater waste.