depends if you are total solution or working solution
total = only 3 of the packs, no other food, drinks being water, black coffee & tea
working solutions - 3 packs & a 600Kcal meals a day, but its only a small piece of fruit allowed I think (?) as most are quite high in carbs, which is waht you are reducing to keep you in ketosis, which means that even on a very low calorie diet, you are not as hungry as you would expect to be