Realistically, it's up to you. The main reason they do it is guidelines from research which state no more than 4 weeks at a time. In reality, it's up to you what you do. We have no CDCs here either, I chose to do add a meal firstly as something to look forward to, but mainly so i learn portion control. The other thing is that the shakes contain everything you need (theoretically) although 0,8g/kilo bodyweight is the usual calculation (for healthy patients/people) and for me thats 51,2g. 3 servings of cambridge only contain 43,2g - i'd have to weigh 54kg (8st 7lb) for that to be right. Thats my target weight and I'll be a skinny minnie then!! If I supplement with 50g chicken (AAM), thats 11g extra protein. But I think it's your call in the end.
Love
Ida xx