You can eat pretty much all of them but only in VERY small quantities and you should avoid the ones high in carbs like potatoes. The point of the diet is to eat more protein then anything else, causing your body to use up its fat stores, as it finds it easier to break down the fat you have stored then the protein you have just eaten.
The diet will make you very lacking in energy and your breath will probably smell foul too.These diets are dangerous and can have serious health disadvantages.The body needs a certain amount of fibre to function properly.