The first three days of the program are the most restrictive, with three meal replacement shakes and 1 protein meal for dinner.
If you have an especially long &/or particularly active day it could be worth adding in a protein snack. Examples would be a hard- boiled egg, small handful of almonds or other nuts, cottage cheese or hummus with non- starchy vegetables, a small can of tinned fish.
Besides the extra protein snack you could also choose some foods from the non- starchy vegetables list to snack on. These will be low in calories but high in nutrients.
BT Nutritionist 🙂