All good.
It is a diet that was formulated back in the '70s by a GP.
It is nutritionally balanced, but quite low calorie, but takes into account that people ALWAYS get hungry on diets, and so the portions reflect this acknowledgement.
It is one of the fastest, yet safest way to lose weight, because diets that place you in ketosis for extended periods of time will actually damage your liver.
Not only that, but diets that create ketosis are fond of using aspartane as a replacement sweetener, but is actually quite bad for you, and if you suffer from dizziness, it will actually exacerbate it!
Anyway, it is not difficult, and you can have a lot of fun on the diet, and if you stay within food groups and portions you can swap around as you please.