You are fine with the 3. The change in recommending 4 came some years after Cambridge was on the market. Cambridge was developed in the UK where they do not abide by our US standards. While in development in hospitals and clinics in the UK over a span of 8 years, their goal was to achieve ketosis and the proper balance of macro-nutrients (protein, fat, and carbohydrate)to protect lean tissues. That was accomplished with the Original 330 formula used 3 xs per day. It was brought here to the USA and everyone did wonderfully. Me included! But here in this country they were recommending more protein at the time (USA has always been a bit protein crazy compared to other countries) in spite of what the 8 years of clinical research had verified was adequate. SO they put a stipulation on the company selling here that to meet the USRDA of protein we should tell people to have 4 servings. With that said, it's up to you. 3 or 4 makes no difference in weight loss and the science showed that 3 was enough. Some days I have a 4th if I feel the need.